publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2013-08-26 | Constraints on the source of ultra-high energy cosmic rays using anisotropy vs chemical composition | The joint analysis of anisotropy signals and chemical composition of
ultra-high energy cosmic rays offers strong potential for shedding light on the
sources of these particles. Following up on an earlier idea, this paper studies
the anisotropies produced by protons of energy >E/Z, assuming that anisotropies
at energy >... | 1308.5699v2 |
2013-09-06 | Probing the origin of the iron K_alpha line around stellar and supermassive black holes using X-ray polarimetry | Asymmetric, broad iron lines are a common feature in the X-ray spectra of
both X-ray binaries (XRBs) and type-1 Active Galactic Nuclei (AGN). It was
suggested that the distortion of the Fe K_alpha emission results from Doppler
and relativistic effects affecting the radiative transfer close to the strong
gravitational w... | 1309.1684v1 |
2013-09-08 | On Iron Monoxide Nanoparticles as a Carrier of the Mysterious 21 Micrometer Emission Feature in Post-Asymptotic Giant Branch Stars | A prominent, mysterious emission feature peaking at ~20.1 micrometer ---
historically known as the ``21 micrometer' feature --- is seen in over two
dozen Galactic and Magellanic Cloud carbon-rich post-asymptotic giant branch
(post-AGB) stars. The nature of its carrier remains unknown since the first
detection of the 21... | 1309.1995v1 |
2013-09-09 | Xenon Reacts with Iron at the Conditions of the Earth's Core | Studies of the Earth's atmosphere have shown that more than 90% of xenon (Xe)
is depleted compared with its abundance in chondritic meteorites. This
long-standing missing Xe paradox has become the subject of considerable
interest and several models for a Xe reservoir have been proposed. Whether the
missing Xe is hiding... | 1309.2169v4 |
2013-09-24 | Mineralogy, reflectance spectra, and physical properties of the Chelyabinsk LL5 chondrite, insight into shock induced changes in asteroid regoliths | The mineralogy and physical properties of Chelyabinsk meteorites (fall,
February 15, 2013) are presented. Three types of meteorite material are
present, described as the light-colored, dark-colored, and impact-melt
lithologies. All are of LL5 composition with the impact-melt lithology being
close to whole-rock melt and... | 1309.6081v6 |
2013-10-14 | Field-induced nematic-like magnetic transition in an iron pnictide superconductor, Ca$_{10}$(Pt$_{3}$As$_{8}$)((Fe$_{1-x}$Pt$_{x}$)$_{2}$As$_{2}$)$_{5}$ | We report a high magnetic field study up to 55 T of the nearly optimally
doped iron-pnictide superconductor Ca$_{10}$(Pt$_{3}$As$_{8}$)
((Fe$_{1-x}$Pt$_{x}$)$_{2}$As$_{2}$)$_{5}$ (x=0.078(6)) with a Tc 10 K using
magnetic torque, tunnel diode oscillator technique and transport measurements.
We determine the superconduc... | 1310.3728v1 |
2013-10-14 | High Pressure Effects on the Superconductivity in Rare-Earth Doped CaFe2As2 | High-pressure superconductivity in a rare-earth doped Ca0.86Pr0.14Fe2As2
single crystalline sample has been studied up to 12 GPa and temperatures down
to 11 K using designer diamond anvil cell under a quasi-hydrostatic pressure
medium. The electrical resistance measurements were complemented by high
pressure and low te... | 1310.3842v2 |
2013-10-17 | Coexistence of orbital degeneracy lifting and superconductivity in iron-based superconductors | In contrast to conventional superconducting (SC) materials, superconductivity
in high-temperature superconductors (HTCs) usually emerges in the presence of
other fluctuating orders with similar or higher energy scales, thus instigating
debates over their relevance for the SC pairing mechanism. In iron-based
superconduc... | 1310.4601v3 |
2013-10-28 | Metal-insulator transition and superconductivity in the two-orbital Hubbard-Holstein model for iron-based superconductors | We investigate a two-orbital model for iron-based superconductors to
elucidate the effect of interplay between electron correlation and Jahn-Teller
electron-phonon coupling by using the dynamical mean-field theory combined with
the exact diagonalization method. When the intra- and inter-orbital Coulomb
interactions, $U... | 1310.7327v3 |
2013-10-29 | A uniform metal distribution in the intergalactic medium of the Perseus cluster of galaxies | Most of the metals (elements heavier than helium) ever produced by stars in
the member galaxies of galaxy clusters currently reside within the hot, X-ray
emitting intra-cluster gas. Observations of X-ray line emission from this
intergalactic medium have suggested a relatively small cluster-to-cluster
scatter outside of... | 1310.7948v1 |
2013-10-30 | Close relationship between superconductivity and the bosonic mode in Ba0.6K0.4Fe2As2 and Na(Fe0.975Co0.025)As | Since the discovery of high temperature superconductivity in the iron
pnictides and chalcogenides in early 2008, a central issue has been the
microscopic origin of the superconducting pairing. Although previous
experiments suggest that the pairing may be induced by exchanging the
antiferromagnetic spin fluctuations and... | 1310.8160v1 |
2013-11-04 | Variability of the High Velocity Outflow in the Quasar PDS 456 | We present a comparison of two Suzaku X-ray observations of the nearby
(z=0.184), luminous ($L_{bol} \sim 10^{47}$ erg s$^{-1}$) type I quasar,
PDS456. A new 125ks Suzaku observation in 2011 caught the quasar during a
period of low X-ray flux and with a hard X-ray spectrum, in contrast to a
previous 190ks Suzaku observ... | 1311.0734v1 |
2013-11-19 | Suzaku View of the Neutron Star in the Dipping Source 4U 1822$-$37 | The dipping X-ray source 4U 1822$-$37 was observed by Suzaku on 2006 Octrober
20 for a net exposure of 37 ks. The source was detected with the XIS at a 1-10
keV flux of 5.5$\times10^{-10}$ erg cm$^{-2}$ s$^{-1}$, and with the HXD
(HXD-PIN) at a 10-50 keV flux of 8.9$\times10^{-10}$ erg cm$^{-2}$ s$^{-1}$.
With HXD-PIN,... | 1311.4618v1 |
2013-11-19 | Metal distributions out to 0.5 r180 in the intracluster medium of four galaxy groups observed with Suzaku | We studied the distributions of metal abundances and metal-mass-to-light
ratios in the intracluster medium (ICM) of four galaxy groups, MKW 4, HCG 62,
the NGC 1550 group, and the NGC 5044 group, out to 0.5 r180 observed with
Suzaku. The Fe abundance decreases with radius, and about 0.2-0.4 solar beyond
0.1 r180. At a g... | 1311.4636v1 |
2013-11-23 | Fermi Surface and Band Structure of (Ca,La)FeAs2 Superconductor from Angle-Resolved Photoemission Spectroscopy | The (Ca,R)FeAs2 (R=La,Pr and etc.) superconductors with a signature of
superconductivity transition above 40 K possess a new kind of block layers that
consist of zig-zag As chains. In this paper, we report the electronic structure
of the new (Ca,La)FeAs2 superconductor investigated by both band structure
calculations a... | 1311.6042v1 |
2013-12-10 | Interfacial mode coupling as the origin of the enhancement of Tc in FeSe films on SrTiO3 | Single unit cell films of iron selenide (1UC FeSe) grown on SrTiO3 (STO)
substrates have recently shown superconducting energy gaps opening at
temperatures close to the boiling point of liquid nitrogen (77 K), a record for
iron-based superconductors. Towards understanding why Cooper pairs form at such
high temperatures... | 1312.2633v6 |
2013-12-17 | Defect ordering and defect-domain wall interactions in PbTiO$_3$: A first-principles study | The properties of ferroelectric materials, such as lead zirconate titanate
(PZT), are heavily influenced by the interaction of defects with domain walls.
These defects are either intrinsic, or are induced by the addition of dopants.
We study here PbTiO$_3$ (the end member of a key family of solid solutions) in
the pres... | 1312.4701v1 |
2014-02-17 | Near-substrate composition depth profile of direct current-plated and pulse-plated Fe-Ni alloys | Composition depth profiles of d.c.-plated and pulseplated Fe-Ni alloys have
been investigated with the reverse depth profile analysis method. When d.c.
plating is applied, the mole fraction of iron near the substrate is higher than
during steadystate deposition since iron is preferentially deposited beside
nickel and t... | 1402.3943v1 |
2014-02-20 | Ultrafast observation of critical nematic fluctuations and giant magnetoelastic coupling in iron pnictides | Many of the iron pnictides have strongly anisotropic normal-state
characteristics, important for the exotic magnetic and superconducting behavior
these materials exhibit. Yet, the origin of the observed anisotropy is unclear.
Electronically driven nematicity has been suggested, but distinguishing this as
an independent... | 1402.4890v1 |
2014-02-21 | The form and the origin of the orbital ordering in the electronic nematic phase of the Iron-based superconductors | We investigated the form of the orbital ordering in the electronic nematic
phase of the Iron-based superconductors by applying a group theoretical
analysis on a realistic five-band model. We find the orbital order can be
either of the inter-orbital s-wave form or the intra-orbital d-wave form. From
the comparison with ... | 1402.5209v1 |
2014-02-24 | Towards a novel laser-driven method of exotic nuclei extraction-acceleration for fundamental physics and technology | The measurement of properties of exotic nuclei, essential for fundamental
nuclear physics, now confronts a formidable challenge for contemporary
radiofrequency accelerator technology. A promising option can be found in the
combination of state-of-the-art high-intensity short pulse laser system and
nuclear measurement t... | 1402.5729v1 |
2014-03-01 | Sudden reversal in the pressure dependence of Tc in the iron-based superconductor CsFe2As2: A possible link between inelastic scattering and pairing symmetry | We report a sudden reversal in the pressure dependence of Tc in the
iron-based superconductor CsFe2As2, similar to that discovered recently in
KFe2As2 [Tafti et al., Nat. Phys. 9, 349 (2013)]. As in KFe2As2, we observe no
change in the Hall coefficient at the zero temperature limit, again ruling out
a Lifshitz transiti... | 1403.0110v3 |
2014-03-05 | Observation of a Robust Zero-energy Bound State in Iron-based Superconductor Fe(Te,Se) | A robust zero-energy bound state (ZBS) in a superconductor, such as a
Majorana or Andreev bound state, is often a consequence of non-trivial
topological or symmetry related properties, and can provide indispensable
information about the superconducting state. Here we use scanning tunneling
microscopy/spectroscopy to de... | 1403.1027v1 |
2014-03-10 | A lithium-ion battery based on a graphene nanoflakes ink anode and a lithium iron phosphate cathode | Li-ion rechargeable batteries have enabled the wireless revolution
transforming global communication. Future challenges, however, demands
distributed energy supply at a level that is not feasible with the current
energy-storage technology. New materials, capable of providing higher energy
density are needed. Here we re... | 1403.2161v1 |
2014-03-26 | Realization of practical level current densities in Sr0.6K0.4Fe2As2 tape conductors for high-field applications | 122 type pnictide superconductors are of particular interest for high-field
applications because of their large upper critical fields Hc2 (> 100 T), low
Hc2 anisotropy r (< 2), and high thin-film critical current densities Jc (> 1
MA/cm2 at 4.2 K). Successful magnet applications require fabrication of
polycrystalline s... | 1403.6704v2 |
2014-04-15 | Orbital phase resolved spectroscopy of GX 301-2 with MAXI | GX 301-2, a bright HMXB with an orbital period of 41.5 days, exhibits stable
periodic orbital intensity modulations with a strong pre-periastron X-ray
flare. Several models have been proposed to explain the accretion at different
orbital phases, invoking accretion via stellar wind, equatorial disk, and
accretion stream... | 1404.3902v1 |
2014-05-01 | The elemental composition of the Sun II. The iron group elements Sc to Ni | We redetermine the abundances of all iron group nuclei in the Sun, based on
neutral and singly-ionised lines of Sc, Ti, V, Mn, Fe, Co and Ni in the solar
spectrum. We employ a realistic 3D hydrodynamic model solar atmosphere,
corrections for departures from local thermodynamic equilibrium (NLTE),
stringent line selecti... | 1405.0287v2 |
2014-05-13 | Intra-unit-cell nematic charge order in the titanium-oxypnictide family of superconductors | Understanding the role played by broken symmetry states such as charge, spin,
and orbital orders in the mechanism of emergent properties such as
high-temperature superconductivity (HTSC) is a major current topic in materials
research. That the order may be within one unit cell, such as nematic, was only
recently consid... | 1405.3236v2 |
2014-05-30 | Evolution of quasiparticle states with and without a Zn-impurity in doped 122 iron pnictides | Based on a minimal two-orbital model [Tai {\it et al.}, Europhys. Lett.
\textbf{103}, 67001 (2013)], which captures the canonical electron-hole-doping
phase diagram of the iron-pnictide BaFe$_{2}$As$_{2}$, we study the evolution
of quasiparticle states as a function of doping using the Bogoliubov-de Gennes
equations wi... | 1406.0027v1 |
2014-06-02 | Superconductivity in titanium-based pnictide oxide compounds | Superconductivity in a novel class of layered materials, Ti-based pnictide
oxides, was recently discovered. These compounds have attracted interest since
they combine features of copper oxide and iron pnictide superconductors. Here
the transition metal (titanium) forms two-dimensional Ti$_2$O layers (anti
structure to ... | 1406.0442v1 |
2014-06-02 | The Distribution of Alpha Elements in Andromeda Dwarf Galaxies | We present alpha to iron abundance ratios for 226 individual red giant branch
stars in nine dwarf galaxies of the Andromeda (M 31) satellite system. The
abundances are measured from the combined signal of Mg, Si, Ca, and Ti lines in
Keck/DEIMOS medium-resolution spectra. This constitutes the first large sample
of alpha... | 1406.0510v1 |
2014-07-11 | Band-edge BCS-BEC crossover in a two-band superconductor: physical properties and detection parameters | Superconductivity in iron-based, magnesium diborides, and other novel
superconducting materials has a strong multi-band and multi-gap character.
Recent experiments support the possibillity for a BCS-BEC crossover induced by
strong-coupling and proximity of the chemical potential to the band edge of one
of the bands. He... | 1407.3109v1 |
2014-07-25 | Spectroscopic parameters for solar-type stars with moderate/high rotation. New parameters for 10 planet-hosts | Planetary studies demand precise and accurate stellar parameters as input to
infer the planetary properties. Different methods often provide different
results that could lead to biases in the planetary parameters. In this work, we
present a refinement of the spectral synthesis technique designed to treat
better more ra... | 1407.6765v1 |
2014-08-14 | Iron based superconductors: A brief overview | Fe-based superconductors were discovered in 2008. This discovery with T$_c$
values up to 56 K, generated a new belief in the field of superconductivity.
Till its discovery, high temperature superconductivity in cuprates, created a
prejudice that Cu-oxides are essential building blocks for a high temperature
superconduc... | 1408.3244v1 |
2014-08-21 | The changing X-ray time lag in MCG-6-30-15 | MCG-6-30-15 is one of the most observed Narrow Line Seyfert 1 galaxies in the
X-ray band. In this paper we examine the X-ray time lags in this source using a
total of 600 ks in observations (440 ks exposure) taken with the XMM-Newton
telescope (300 ks in 2001 and 300 ks in 2013). Both the old and new
observations show ... | 1408.5051v1 |
2014-09-01 | Chemical Evolution on the Scale of Clusters of Galaxies: A Conundrum? | The metal content of clusters of galaxies and its relation to their stellar
content is revisited making use of a cluster sample for which all four basic
parameters are homogeneously measured within consistent radii, namely
core-excised mass-weighted metallicity plus total, stellar and ICM masses. For
clusters of total ... | 1409.0307v1 |
2014-09-05 | Ceci n'est pas a globular cluster: the metallicity distribution of the stellar system Terzan 5 | We present new determinations of the iron abundance for 220 stars belonging
to the stellar system Terzan 5 in the Galactic bulge. The spectra have been
acquired with FLAMES at the Very Large Telescope of the European Southern
Observatory and DEIMOS at the Keck II Telescope. This is by far the largest
spectroscopic samp... | 1409.1682v1 |
2014-09-15 | Do cluster properties affect the quenching rate? | The quenching rate is known to depend on galaxy stellar mass and environment,
however, possible dependences on the hosting halo properties, such as mass,
richness, and dynamical status, are still debated. The determination of these
dependences is hampered by systematics, induced by noisy estimates of cluster
mass or by... | 1409.4416v1 |
2014-09-23 | Structural and Magnetic Phase Diagram of CrAs and its Relationship with Pressure-induced Superconductivity | Most unconventional superconductors, including cuprates and iron-based
superconductors, are derived from chemical doping or application of pressure on
their collinearly magnetic-ordered parent compounds[1-5]. The recently
discovered pressure-induced superconductor CrAs, as a rare example of a
non-collinear helimagnetic... | 1409.6615v3 |
2014-09-29 | Disk emission and absorption lines in LMXB. Note on the physical conditions of an absorbing material | We show that the continuum X-ray spectrum of 4U 1630-472 with iron absorption
lines can be satisfactorily modeled by the spectrum from an accretion disk
atmosphere. We performed full radiative transfer calculations using our code
ATM21 to model the emission from an accretion disk surface that is seen at
different viewi... | 1409.8052v1 |
2014-11-03 | Discovery of a ~2 hr high frequency X-ray QPO and iron K alpha reverberation in the active galaxy MS 2254.9-3712 | We report the discovery of a $\sim 1.5 \times 10^{-4}$ Hz ($\sim 2$ hr) X-ray
quasi-periodic oscillation (QPO) in the active galaxy MS 2254.9-3712, using a
$\sim 70$ ks XMM-Newton observation. The QPO is significantly detected ($\sim
3.3 \sigma$) in the $1.2 - 5.0$ keV band only, connecting its origin with the
primary ... | 1411.0684v2 |
2014-11-06 | Ising-nematic order in the bilinear-biquadratic model for the iron pnictides | Motivated by the recent inelastic neutron scattering (INS) measurements in
the iron pnictides which show a strong anisotropy of spin excitations in
directions perpendicular and parallel to the ordering wave-vector even above
the magnetic transition temperature $T_N$, we study the frustrated Heisenberg
model with a biqu... | 1411.1462v2 |
2014-11-07 | Phase-resolved spectroscopy of low frequency quasi-periodic oscillations in GRS 1915+105 | X-ray radiation from black hole binary (BHB) systems regularly displays
quasi-periodic oscillations (QPOs). In principle, a number of suggested
physical mechanisms can reproduce their power spectral properties, thus more
powerful diagnostics which preserve phase are required to discern between
different models. In this... | 1411.1967v1 |
2014-11-19 | The Seyfert 2 galaxy NGC 2110: hard X-ray emission observed by NuSTAR and variability of the iron K$α$ line | We present NuSTAR observations of the bright Seyfert 2 galaxy NGC 2110
obtained in 2012, when the source was at the highest flux level ever observed,
and in 2013, when the source was at a more typical flux level. We include
archival observations from other X-ray satellites, namely XMM-Newton, Suzaku,
BeppoSAX, Chandra ... | 1411.5151v1 |
2014-11-20 | The Role of the Magnetorotational Instability in Massive Stars | The magnetorotational instability (MRI) is key physics in accretion disks and
is widely considered to play some role in massive-star core collapse. Models of
rotating massive stars naturally develop very strong shear at composition
boundaries, a necessary condition for MRI instability, and the MRI is subject
to triply-... | 1411.5714v1 |
2014-12-05 | A NuSTAR observation of the fast symbiotic nova V745 Sco in outburst | The fast recurrent nova V745 Sco was observed in the 3-79 keV X-rays band
with NuSTAR 10 days after the optical discovery. The measured X-ray emission is
consistent with a collisionally ionized optically thin plasma at temperature of
about 2.7 keV. A prominent iron line observed at 6.7 keV does not require
enhanced iro... | 1412.2088v2 |
2014-12-09 | The final fate of stars that ignite neon and oxygen off-center: electron capture or iron core-collapse supernova? | In the ONeMg cores of $8.8-9.5~{\rm M}_\odot$ stars, neon and oxygen burning
is ignited off-center. Whether the neon-oxygen flame propagates to the center
is critical to determine whether these stars undergo Fe core collapse or
electron capture induced ONeMg core collapse. We present more details of stars
that ignite n... | 1412.2878v2 |
2014-12-15 | Synthesis, Structural, and Transport Properties of Cr-doped BaTi_2As_2O | The interplay between unconventional superconductivity and the ordering of
charge/spin density wave is one of the most vital issues in both condensed
matter physics and material science. The Ti-based compound BaTi_2As_2O, which
can be seen as the parent phase of superconducting BaTi_2Sb_2O, has a layered
structure with... | 1412.4469v1 |
2014-12-16 | Characterization of 3 mm Glass Electrodes and Development of RPC Detectors for $INO-ICAL$ Experiment | India-based Neutrino Observatory (INO) is a multi-institutional facility,
planned to be built up in South India. The INO facility will host a 51 kton
magnetized Iron CALorimeter (ICAL) detector to study atmospheric muon
neutrinos. Iron plates have been chosen as the target material whereas
Resistive Plate Chambers (RPC... | 1412.4998v1 |
2014-12-16 | Thermally Induced Chemistry of Meteoritic Complex Organic Molecules: A New Heat-Diffusion Model for the Atmospheric Entry of Meteorites | Research over the past four decades has shown a rich variety of complex
organic molecular content in some meteorites. This current study is an attempt
to gain a better insight into the thermal conditions experienced by these
molecules inside meteorites during atmospheric entry. In particular, we wish to
understand poss... | 1412.5134v3 |
2014-12-19 | Universal V-shaped temperature-pressure phase diagram in the iron-based superconductors KFe2As2, RbFe2As2, and CsFe2As2 | We report a sudden reversal in the pressure dependence of Tc in the
iron-based superconductor RbFe2As2, at a critical pressure Pc = 11 kbar.
Combined with our prior results on KFe2As2 and CsFe2As2, we find a universal
V-shaped phase diagram for Tc vs P in these fully hole-doped 122 materials,
when measured relative to ... | 1412.6196v2 |
2014-12-19 | Resonant inelastic x-ray scattering study of electronic excitations in insulating K$_{0.83}$Fe$_{1.53}$Se$_2$ | We report an Fe $K$-edge resonant inelastic X-ray scattering (RIXS) study of
K$_{0.83}$Fe$_{1.53}$Se$_2$. This material is an insulator, unlike many parent
compounds of iron-based superconductors. We found a sharp excitation around 1
eV, which is resonantly enhanced when the incident photon energy is tuned near
the pre... | 1412.6429v2 |
2014-12-22 | Inverse magneto-refraction as a mechanism for laser modification of spin-spin exchange parameters and subsequent terahertz emission from iron oxides | Ultrafast non-thermal manipulation of magnetization by light relies on either
indirect coupling of the electric field component of the light with spins via
spin-orbit interaction or direct coupling between the magnetic field component
and spins. Here we propose a novel scenario for coupling between the electric
field o... | 1412.7094v1 |
2014-12-24 | Tests of the nuclear equation of state and superfluid and superconducting gaps using the Cassiopeia A neutron star | The observed rapid cooling of the Cassiopeia A neutron star can be
interpreted as being caused by neutron and proton transitions from normal to
superfluid and superconducting states in the stellar core. Here we present two
new Chandra ACIS-S Graded observations of this neutron star and measurements of
the neutron star ... | 1412.7759v2 |
2015-01-07 | Detoxification of superoxide without production of H2O2: antioxidant activity of superoxide reductase complexed with ferrocyanide | The superoxide radical O(2)(-.) is a toxic by-product of oxygen metabolism.
Two O(2)(-.) detoxifying enzymes have been described so far, superoxide
dismutase and superoxide reductase (SOR), both forming H2O2 as a reaction
product. Recently, the SOR active site, a ferrous iron in a [Fe(2+) (N-His)(4)
(S-Cys)] pentacoord... | 1501.01439v1 |
2015-01-12 | X-ray Probes of Black Hole Accretion Disks for Testing the No-Hair Theorem | The spins of a number of supermassive and stellar-mass black holes have been
measured based on detections of thermal continuum emission and relativistically
broadened iron lines in their x-ray spectra. Likewise, quasiperiodic
variability has been observed in several sources. Such measurements commonly
make the assumpti... | 1501.02815v1 |
2015-01-22 | Mathematical analysis of the $PO_4$-$DOP$-$Fe$ marine ecosystem model driven by 3-D ocean transport | Marine ecosystem models are developed to understand and simulate the
biogeochemical processes involved in marine ecosystems. Parekh, Follows and
Boyle introduced the $PO_4$-$DOP$-$Fe$ model of the coupled phosphorus and iron
cycles in 2005. Especially the part describing the phosphorus cycle
($PO_4$-$DOP$ model) is oft... | 1501.05428v1 |
2015-01-26 | Origin of the non-monotonic variance of Tc in the 1111 iron based superconductors with isovalent doping | Motivated by recent experimental investigations of the isovalent doping
iron-based superconductors LaFe(AsxP1-x)O1-yFy and NdFe(AsxP1-x)O1-yFy we
theoretically study the correlation between the local lattice structure, the
Fermi surface, the spin fluctuation-mediated superconductivity, and the
composition ratio. In the... | 1501.06303v1 |
2015-03-03 | Tunable room-temperature ferromagnet using an iron-oxide and graphene oxide nanocomposite | Magnetic materials have found wide application ranging from electronics and
memories to medicine. Essential to these advances is the control of the
magnetic order. To date, most room-temperature applications have a fixed
magnetic moment whose orientation is manipulated for functionality. Here we
demonstrate an iron-oxi... | 1503.00960v1 |
2015-03-03 | Dark Matter Balls Help Supernovae to Explode | As a solution to the well-known problem that the shock wave potentially
responsible for the explosion of a supernova actually tends to stall, we
propose a new energy source arising from our model for dark matter. Our earlier
model proposed that dark matter should consist of cm-large white dwarf-like
objects kept togeth... | 1503.01089v2 |
2015-03-05 | Distinctive momentum dependence of the band reconstruction in the nematic state of FeSe thin film | Nematic state, where the system is translationally invariant but breaks the
rotational symmetry, has drawn great attentions recently due to experimental
observations of such a state in both cuprates and iron-based superconductors.
The mechanism of nematicity that is likely tied to the pairing mechanism of
high-Tc, howe... | 1503.01556v1 |
2015-03-09 | Determination of the spectroscopic stellar parameters for 257 field giant stars | The study of stellar parameters of planet-hosting stars, such as metallicity
and chemical abundances, help us to understand the theory of planet formation
and stellar evolution. Here, we present a catalogue of accurate stellar
atmospheric parameters and iron abundances for a sample of 257 K and G field
evolved stars th... | 1503.02556v1 |
2015-03-10 | Detailed Abundances of 15 Stars in the Metal-Poor Globular Cluster NGC 4833 | We have observed 15 red giant stars in the relatively massive, metal-poor
globular cluster NGC 4833 using the Magellan Inamori Kyocera Echelle
spectrograph at Magellan. We calculate stellar parameters for each star and
perform a standard abundance analysis to derive abundances of 43 species of 39
elements, including 20... | 1503.03079v2 |
2015-03-11 | Molecular Beam Epitaxy Growth of Superconducting LiFeAs Film on SrTiO3(001) Substrate | The stoichiometric "111" iron-based superconductor, LiFeAs, has attacted
great research interest in recent years. For the first time, we have
successfully grown LiFeAs thin film by molecular beam epitaxy (MBE) on
SrTiO3(001) substrate, and studied the interfacial growth behavior by
reflection high energy electron diffr... | 1503.03216v1 |
2015-03-11 | Simulations Study of Muon Response in the Peripheral Regions of the Iron Calorimeter Detector at the India-based Neutrino Observatory | The magnetized Iron CALorimeter detector (ICAL) which is proposed to be built
in the India-based Neutrino Observatory (INO) laboratory, aims to study
atmospheric neutrino oscillations primarily through charged current
interactions of muon neutrinos and anti-neutrinos with the detector. The
response of muons and charge ... | 1503.03369v1 |
2015-03-16 | Spectral properties of the soft excess pulsar RX J0059.2-7138 during its 2013 outburst | We report on an X-ray observation of the Be X-ray Binary Pulsar RX
J0059.2-7138, performed by XMM-Newton in March 2014. The 19 ks long observation
was carried out about three months after the discovery of the latest outburst
from this Small Magellanic Cloud transient, when the source luminosity was Lx ~
10$^{38}$ erg/s... | 1503.04574v1 |
2015-03-20 | Relative Abundance Measurements in Plumes and Interplumes | We present measurements of relative elemental abundances in plumes and
interplumes. Plumes are bright, narrow structures in coronal holes that extend
along open magnetic field lines far out into the corona. Previous work has
found that in some coronal structures the abundances of elements with a low
first ionization po... | 1503.06044v1 |
2015-04-01 | The Case for a Hot Archean Climate and its Implications to the History of the Biosphere | The case for a much warmer climate on the early Earth than now is presented.
The oxygen isotope record in sedimentary chert and the compelling case for a
near constant isotopic oxygen composition of seawater over geologic time
support thermophilic surface temperatures prevailing in the Archean, with some
support for ho... | 1504.00401v1 |
2015-05-05 | Direct evidence for the emergence of a pressure induced nodal superconducting gap in the iron-based superconductor Ba_0.65Rb_0.35Fe_2As_2 | Identifying the superconducting (SC) gap structure of the iron-based
high-temperature superconductors (Fe-HTS's) remains a key issue for the
understanding of superconductivity in these materials. In contrast to other
unconventional superconductors, in the Fe-HTS's both $d$-wave and extended
s-wave pairing symmetries ar... | 1505.01223v1 |
2015-05-08 | Magnetic spin moment reduction in photoexcited ferromagnets through exchange interaction quenching: Beyond the rigid band approximation | The exchange interaction among electrons is one of the most fundamental
quantum mechanical interactions in nature and underlies any magnetic phenomena
from ferromagnetic ordering to magnetic storage. The current technology is
built upon a thermal or magnetic field, but a frontier is emerging to directly
control magneti... | 1505.01904v1 |
2015-05-23 | Common Electronic Origin of Superconductivity in (Li,Fe)OHFeSe Bulk Superconductor and Single-Layer FeSe/SrTiO3 Films | The mechanism of high temperature superconductivity in the iron-based
superconductors remains an outstanding issue in condensed matter physics. The
electronic structure, in particular the Fermi surface topology, is considered
to play an essential role in dictating the superconductivity. Recent revelation
of distinct el... | 1505.06361v1 |
2015-05-29 | Impact of oxygen doping and oxidation state of iron on the electronic and magnetic properties of BaFeO$_{3-δ} | We studied structural, electronic and magnetic properties of a cubic
perovskite BaFeO$_{3-\delta}$ ($0 \le \delta \le 0.5$) within the density
functional theory using a generalized gradient approximation and a GGA+U
method. According to our calculations, BaFeO$_3$ in its stoichiometric cubic
structure should be half-me... | 1505.07942v1 |
2015-06-04 | Weak and strong electronic correlations in Fe superconductors | In this chapter the strength of electronic correlations in the normal phase
of Fe-superconductors is discussed. It will be shown that the agreement between
a wealth of experiments and DFT+DMFT or similar approaches supports a scenario
in which strongly-correlated and weakly-correlated electrons coexist in the
conductio... | 1506.01678v1 |
2015-06-15 | Simultaneous spectral and reverberation modelling of relativistic reflection in Mrk 335 | We present an X-ray spectral and timing model to investigate the broad and
variable iron line seen in the high flux state of Mrk 335. The model consists
of a variable X-ray source positioned along the rotation axis of the black hole
that illuminates the accretion disc producing a back-scattered, ionized
reflection spec... | 1506.04524v1 |
2015-07-07 | The NuSTAR X-ray spectrum of the low-luminosity AGN in NGC 7213 | We present an analysis of the 3-79 keV NuSTAR spectrum of the low-luminosity
active galactic nucleus NGC 7213. In agreement with past observations, we find
a lower limit to the high-energy cut-off of Ec > 140 keV, no evidence for a
Compton-reflected continuum, and the presence of an iron Kalpha complex,
possibly produc... | 1507.01775v1 |
2015-07-09 | The phase diagrams of iron-based superconductors: theory and experiments | Phase diagrams play a primary role in the understanding of materials
properties. For iron-based superconductors (Fe-SC), the correct definition of
their phase diagrams is crucial because of the close interplay between their
crystallo-chemical and magnetic properties, on one side, and the possible
coexistence of magneti... | 1507.02406v1 |
2015-07-09 | Stability of Two-Dimensional Iron-Carbides Suspended across Graphene Pores: First-principles Particle Swarm Optimization | Inspired by recent experimental realizations of two-dimensional (2D) metals
and alloys, we theoretically investigate the stability and electronic
properties of monolayer (ML) Fe-C compounds and pure Fe. According to our and
others theoretical results, the experiment [Science 343, 1228 (2014)] proposed
ML pure Fe square... | 1507.02418v2 |
2015-07-09 | Chemical Abundances in the PN Wray16-423 in the Sagittarius Dwarf Spheroidal Galaxy: Constraining the Dust Composition | We performed a detailed analysis of elemental abundances, dust features, and
polycyclic aromatic hydrocarbons (PAHs) in the C-rich planetary nebula (PN)
Wray16-423 in the Sagittarius dwarf spheroidal galaxy, based on a unique
dataset taken from the Subaru/HDS, MPG/ESO FEROS, HST/WFPC2, and Spitzer/IRS.
We performed the... | 1507.02667v1 |
2015-08-07 | Correlation-enhanced odd-parity inter-orbital singlet pairing in the iron-pnictide superconductor LiFeAs | The rich variety of iron-based superconductors and their complex electronic
structure lead to a wide range of possibilities for gap symmetry and pairing
components. Here we solve in the 2-Fe Brillouin zone the full
frequency-dependent linearized Eliashberg equations for LiFeAs with
spin-fluctuation mediated pairing int... | 1508.01789v4 |
2015-08-21 | Computational searches for iron oxides at high pressures | We have used density-functional-theory methods and the ab initio random
structure searching (AIRSS) approach to predict stable structures and
stoichiometries of mixtures of iron and oxygen at high pressures. Searching was
performed for 12 different stoichiometries at pressures of 100, 350 and 500
GPa, which involved re... | 1508.05247v1 |
2015-09-03 | The Gaia-ESO Survey: chemical signatures of rocky accretion in a young solar-type star | It is well known that newly formed planetary systems undergo processes of
orbital reconfiguration and planetary migration. As a result, planets or
protoplanetary objects may accrete onto the central star, being fused and mixed
into its external layers. If the accreted mass is sufficiently high and the
star has a suffic... | 1509.00933v2 |
2015-09-05 | Two-Dimensional Oxide Topological Insulator With Iron-Pnictide Superconductor LiFeAs Structure | By using first-principles calculations, we propose that ZrSiO can be looked
as a three-dimensional (3D) oxide weak topological insulator (TI) and its
single layer is a long-sought-after 2D oxide TI with a band gap up to 30 meV.
Calculated phonon spectrum of the single layer ZrSiO indicates it is
dynamically stable and ... | 1509.01686v2 |
2015-09-11 | New opacity measurement principle for LMJ-PETAL laser facility | Stellar seismology reveals some interior properties of thousands of
solar-type stars but the solar seismic sound speed stays puzzling since a
decade as it disagrees with the Standard Solar Model (SSM) prediction. One of
the explanations of this disagreement may be found in the treatment of the
transport of radiation fr... | 1509.03563v1 |
2015-09-17 | Local Radiation Hydrodynamic Simulations of Massive Star Envelopes at the Iron Opacity Peak | We perform three dimensional radiation hydrodynamic simulations of the
structure and dynamics of radiation dominated envelopes of massive stars at the
location of the iron opacity peak. One dimensional hydrostatic calculations
predict an unstable density inversion at this location, whereas our simulations
reveal a comp... | 1509.05417v1 |
2015-09-18 | Origin of the spectral upturn in the cosmic-ray C/Fe and O/Fe ratios | The observed spectrum of Galactic cosmic rays has several exciting features
such as the rise in the positron fraction above ~10 GeV of energy and the
spectral hardening of protons and helium at ~300 GeV/nucleon of energy. The
ATIC-2 experiment has recently reported an unexpected spectral upturn in the
elemental ratios ... | 1509.05774v1 |
2015-09-23 | Anisotropic hyperfine interactions in FeP studied by 57Fe Mossbauer spectroscopy and 31P NMR | We report results of 57Fe Mossbauer and 31P NMR studies of a phosphide FeP
powder sample performed in a wide temperature range including the point (TN ~
120 K) of magnetic phase transitions. The 57Fe Mossbauer spectra at low
temperatures T < TN consist of very diffuse Zeeman pattern with line
broadenings and sizeable s... | 1509.06953v2 |
2015-09-23 | The 1999aa-like Type Ia Supernova iPTF14bdn in the Ultraviolet and Optical | We present ultraviolet (UV) and optical photometry and spectra of the
1999aa-like supernova (SN) iPTF14bdn. The UV data were observed using the Swift
Ultraviolet/Optical Telescope (UVOT) and constitute the first UV spectral
series of a 1999aa-like SN. From the photometry we measure $\Delta m_{15}({\it
B})\,=\,0.84 \pm0... | 1509.07129v1 |
2015-11-11 | Discovery of Extremely Broad Balmer Absorption Lines in SDSS J152350.42+391405.2 | We present the discovery of Balmer line absorption from H$\alpha$ to
H$\gamma$ in an iron low-ionization broad absorption line (FeLoBAL) quasar SDSS
J152350.42+391405.2 (hereafter J1523), by the quasi-simultaneous optical and
near-infrared spectroscopy. The Balmer line absorption is at $z_{absor}$ =
0.6039 +/-0.0021 an... | 1511.03422v1 |
2015-12-17 | The Fe/Ni ratio in ionized nebulae: clues on dust depletion patterns | We perform a homogeneous analysis of the Fe/Ni abundance ratio in eight
Galactic planetary nebulae (PNe) and three Galactic H II regions that include
the Orion nebula, where we study four nebular zones and one shocked region. We
use [Fe ii], [Fe iii], and [Ni iii] lines, and ionization correction factors
(ICFs) that ac... | 1512.05664v1 |
2015-12-18 | Expansion of the tetragonal magnetic phase with pressure in the iron-arsenide superconductor Ba{1-x}KxFe2As2 | In the temperature-concentration phase diagram of most iron-based
superconductors, antiferromagnetic order is gradually suppressed to zero at a
critical point, and a dome of superconductivity forms around that point. The
nature of the magnetic phase and its fluctuations is of fundamental importance
for elucidating the ... | 1512.05912v1 |
2015-12-22 | Dome-shaped magnetic order competing with high-temperature superconductivity at high pressures in FeSe | The coexistence and competition between superconductivity and electronic
orders, such as spin or charge density waves, have been a central issue in high
transition-temperature (${T_{\rm c}}$) superconductors. Unlike other iron-based
superconductors, FeSe exhibits nematic ordering without magnetism whose
relationship wi... | 1512.06951v1 |
2015-12-27 | Two types of superconducting domes in unconventional superconductors | Uncovering the origin of unconventional superconductivity is often plagued by
the overwhelming material diversity with varying normal and superconducting
(SC) properties. In this article, we deliver a comprehensive study of the SC
properties and phase diagrams using multiple tunings (such as disorder,
pressure or magne... | 1512.08186v2 |
2016-01-04 | An Intermediate Type Ia Supernova Between Normal And Super-Chandrasekhar | In this paper, we report observations of a peculiar Type Ia supernova
iPTF13asv (a.k.a., SN2013cv) from the onset of the explosion to months after
its peak. The early-phase spectra of iPTF13asv show absence of iron absorption,
indicating that synthesized iron elements are confined to low-velocity regions
of the ejecta,... | 1601.00686v2 |
2016-01-21 | The temperature and chronology of heavy-element synthesis in low-mass stars | Roughly half of the heavy elements (atomic mass greater than that of iron)
are believed to be synthesized in the late evolutionary stages of stars with
masses between 0.8 and 8 solar masses. Deep inside the star, nuclei (mainly
iron) capture neutrons and progressively build up (through the
slow-neutron-capture process,... | 1601.05640v1 |
2016-01-21 | Detailed magnetic and structural analysis mapping a robust magnetic C4 dome in Sr1-xNaxFe2As2 | The recently discovered $C_4$ tetragonal magnetic phase in hole-doped members
of the iron-based superconductors provides new insights into the origin of
unconventional superconductivity. Previously observed in
Ba$_{1-x}A_x$Fe$_2$As$_2$ (with $A =$ K, Na), the $C_4$ magnetic phase exists
within the well studied $C_2$ sp... | 1601.05693v1 |
2016-02-11 | Doping evolution of the superconducting gap structure in the underdoped iron arsenide Ba1-xKxFe2As2 revealed by thermal conductivity | The thermal conductivity kappa of the iron-arsenide superconductor
Ba1-xKxFe2As2 was measured for heat currents parallel and perpendicular to the
tetragonal c axis at temperatures down to 50 mK and in magnetic fields up to 15
T. Measurements were performed on samples with compositions ranging from
optimal doping (x = 0... | 1602.03914v1 |
2016-03-03 | Fe dopant in ZnO: 2+ vs 3+ valency and ion-carrier s,p-d exchange interaction | Dopants of transition metal ions in II-VI semiconductors exhibit native 2+
valency. Despite this, 3+ or mixed 3+/2+ valency of iron ions in ZnO was
reported previously. Several contradictory mechanisms have been put forward for
explanation of this fact so far. Here, we analyze Fe valency in ZnO by
complementary theoret... | 1603.01123v2 |
2016-03-05 | Development and characterization of single gap glass RPC | India-based Neutrino Observatory (INO) facility is going to have a 50 kton
magnetized Iron CALorimeter (ICAL) detector for precision measurements of
neutrino oscillations using atmospheric neutrinos. The proposed ICAL detector
will be a stack of magnetized iron plates (acting as target material)
interleaved with glass ... | 1603.01719v5 |
2016-03-09 | Suppression of spin-exciton state in hole overdoped iron-based superconductors | The mechanism of Cooper pair formation in iron-based superconductors remains
a controversial topic. The main question is whether spin or orbital
fluctuations are responsible for the pairing mechanism. To solve this problem,
a crucial clue can be obtained by examining the remarkable enhancement of
magnetic neutron scatt... | 1603.02762v1 |
2016-03-17 | The origin of the $α$-enhancement of massive galaxies | We study the origin of the stellar $\alpha$-element-to-iron abundance ratio,
$[\alpha/\mathrm{Fe}]_{\ast}$, of present-day central galaxies, using
cosmological, hydrodynamical simulations from the Evolution and Assembly of
GaLaxies and their Environments (EAGLE) project. For galaxies with stellar
masses of $M_{\ast} > ... | 1603.05653v3 |
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