publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2013-06-25 | Photo-Disintegration of the Iron Nucleus in Fractured Magnetite Rocks with Magnetostriction | There has been considerable interest in recent experiments on iron nuclear
disintegrations observed when rocks containing such nuclei are crushed and
fractured. The resulting nuclear transmutations are particularly strong for the
case of magnetite rocks, i.e. loadstones. We argue that the fission of the iron
nucleus is... | 1306.6286v1 |
2013-07-29 | Review of nuclear magnetic resonance studies on iron-based superconductors | The newly discovered iron-based superconductors have triggered renewed
enormous research interest in the condensed matter physics community. Nuclear
magnetic resonance (NMR) is a low-energy local probe for studying strongly
correlated electrons, and particularly important for high-$T_{\rm C}$
superconductors. In this p... | 1307.7528v1 |
2013-08-12 | The substitution effects on electronic structure of iron selenide superconductors | The influence of a partial substitution with S, Te, Co, Ni and Cu atoms on
the electronic structure of the FeSe superconductor has been investigated
within the density functional theory. The results of the supercell calculations
reveal distinct changes of electronic structures of the substituted FeSe
systems, which can... | 1308.2508v1 |
2013-09-19 | Investigation of atomic and electronic structures of MgOFeSe studied by the first-principles calculations | In order to assist the search of new superconductors in iron selenide
materials by intercalation, we calculate the crystal and electronic structures
of MgOFeSe using the first-principles density functional theory. MgOFeSe is
isotructural to the parent compound of iron pnictide superconductor LaOFeAs. In
LaOFeAs, the an... | 1309.5079v2 |
2013-09-27 | Constrained non-collinear magnetism in disordered Fe and Fe-Cr alloys | The development of quantitative models for radiation damage effects in iron,
iron alloys and steels, particularly for the high temperature properties of the
alloys, requires understanding of magnetic interactions, which control the
phase stability of ferritic-martensitic, ferritic, and austenitic steels. In
this work, ... | 1309.7183v1 |
2013-10-23 | The non-magnetic collapsed tetragonal phase of CaFe2As2 and superconductivity in the iron pnictides | The relationship between antiferromagnetic spin fluctuations and
superconductivity has become a central topic of research in studies of
superconductivity in the iron pnictides. We present unambiguous evidence of the
absence of magnetic fluctuations in the non-superconducting collapsed
tetragonal phase of CaFe2As2 via i... | 1310.6346v1 |
2013-11-11 | Model of the Electronic Structure of Electron-Doped Iron-Based Superconductors: Evidence for Enhanced Spin Fluctuations by Diagonal Electron Hopping | We present a theoretical understanding of the superconducting phase diagram
of the electron-doped iron pnictides. We show that, besides the Fermi surface
nesting, a peculiar motion of electrons, where the next nearest neighbor
(diagonal) hoppings between iron sites dominate over the nearest neighbor ones,
plays an impo... | 1311.2413v2 |
2013-11-23 | Thirty Femtograms Detection of Iron in Mammalian Cells | Inorganic nanomaterials and particles with enhanced optical, mechanical or
magnetic attributes are currently being developed for a wide range of
applications. Safety issues have been formulated however concerning their
potential cyto- and genotoxicity. For in vivo and in vitro experimentations,
recent developments have... | 1311.6019v1 |
2013-12-20 | Enhancing the three-dimensional electronic structure in 1111-type iron arsenide superconductors by H-substitution | The 1111-type iron arsenide hydride CaFe1-xCoxAsH was synthesized by
high-pressure solid-state reaction, and its electronic structure and
superconducting properties were investigated. Bulk superconductivity was
observed at x = 0.07-0.26. A maximum superconducting critical temperature Tcmax
of 23 K was observed at x = 0... | 1312.5818v2 |
2013-12-20 | Band antiferromagnetism in a two-band model for iron pnictides | In this work I investigate a two-band Hubbard model using the Gutzwiller
wavefunction. The tight-binding part of the model was constructed to have a
gapless spin-density wave state which leads to Dirac points in the
bandstructure, a common feature of many iron-pnictide compounds. For quarter,
half and three-quarter fil... | 1312.5902v2 |
2013-12-29 | Electron capture of iron group nuclei in magnetars | Using the theory of relativity in superstrong magnetic fields (SMFs) and
nuclear shell model, we carry out estimation for electron capture (EC) rates on
iron group nuclei in SMFs. The rates of change of electronic abundance (RCEA)
due to EC are also investigated in SMFs. It is concluded that the EC rates of
most iron g... | 1312.7552v1 |
2014-02-17 | Electronic Nematicity Revealed by Torque Magnetometry in Iron Arsenide EuFe$_2$(As$_{1-x}$P$_x$)$_2$ | Electronic nematics, an electron orientational order which breaks the
underlying rotational symmetry, have been observed in iron pnictide
superconductors several years after their discovery. However, the universality
of the doping dependence of this phase and its relation to other
symmetry-breaking orders (such as supe... | 1402.4124v1 |
2014-03-01 | Doping dependence of the anisotropic quasiparticle interference in NaFe1-xCoxAs iron-based superconductors | We use scanning tunneling microscopy to investigate the doping dependence of
quasiparticle interference (QPI) in NaFe1-xCoxAs iron-based superconductors.
The goal is to study the relation between nematic fluctuations and Cooper
pairing. In the parent and underdoped compounds, where four-fold rotational
symmetry is brok... | 1403.0090v1 |
2014-03-07 | The origin of low [alpha/Fe] ratios in extremely metal-poor stars | We show that the low ratios of $\alpha$ elements (Mg, Si, and Ca) to Fe
recently found for a small fraction of extremely metal-poor stars can be
naturally explained with the nucleosynthesis yields of core-collapse
supernovae, i.e., $13-25M_\odot$ supernovae, or hypernovae. For the case
without carbon enhancement, the e... | 1403.1796v1 |
2014-03-07 | Iron based high transition temperature superconductors | In a superconductor electrons form pairs and electric transport becomes
dissipation-less at low temperatures. Recently discovered iron based
superconductors have the highest superconducting transition temperature next to
copper oxides. In this article, we review material aspects and physical
properties of iron based su... | 1403.2612v1 |
2014-03-24 | Majorana edge states and topological properties in 1D/2D Rashba semiconductor proximity coupled to iron-based superconductor | We study Majorana edge states and their topological properties of
one-dimensional(1D) and two-dimensional(2D) Rashba semiconductor deposited on
iron-based superconductor under the applied Zeeman field for various
directions. Using the recursive Green's function method, we calculate the local
density of states(LDOS) bot... | 1403.5857v2 |
2014-03-25 | Electronic correlations determine the phase stability of iron up to the melting temperature | We present theoretical results on the high-temperature phase stability and
phonon spectra of paramagnetic bcc iron which explicitly take into account
many-body effects. Several peculiarities, including a pronounced softening of
the [110] transverse (T$_1$) mode and a dynamical instability of the bcc
lattice in harmonic... | 1403.6497v1 |
2014-04-24 | A Tentative Size-Luminosity Relation for the Iron Emission-Line Region in Quasars | New reverberation mapping measurements of the size of the optical iron
emission-line region in quasars are provided, and a tentative size-luminosity
relation for this component is reported. Combined with lag measurements in
low-luminosity sources, the results imply an emission-region size that is
comparable to and at m... | 1404.6142v1 |
2014-05-14 | Observations of MCG-5-23-16 with Suzaku, XMM-Newton and NuSTAR: Disk tomography and Compton hump reverberation | MCG-5-23-16 is one of the first AGN where relativistic reverberation in the
iron K line originating in the vicinity of the supermassive black hole was
found, based on a short XMM-Newton observation. In this work, we present the
results from long X-ray observations using Suzaku, XMM-Newton and NuSTAR
designed to map the... | 1405.3674v1 |
2014-05-22 | Intrinsic Josephson junctions in the iron-based multi-band superconductor (V2Sr4O6)Fe2As2 | In layered superconductors, Josephson junctions may be formed within the unit
cell due to sufficiently low interlayer coupling. These intrinsic Josephson
junction (iJJ) systems have attracted considerable interest for their
application potential in quantum computing as well as efficient sources of THz
radiation, closin... | 1405.5693v1 |
2014-05-27 | Disorder-induced topological change of the superconducting gap structure in iron pnictides | In superconductors with unconventional pairing mechanisms, the energy gap in
the excitation spectrum often has nodes, which allow quasiparticle excitations
at low energies. In many cases, e.g. $d$-wave cuprate superconductors, the
position and topology of nodes are imposed by the symmetry, and thus the
presence of gapl... | 1405.6951v2 |
2014-06-03 | Magnetic spectra in the tridiminished-icosahedron \{Fe$_9$\} nano-cluster by inelastic neutron scattering | Inelastic neutron scattering (INS) experiments under applied magnetic field
at low temperatures show detailed low lying magnetic excitations in the so
called tridiminshed iron icosahedron magnetic molecule. The magnetic molecule
consists of nine iron Fe$^{3+}$ ($s = 5/2$) and three phosphorous atoms that
are situated o... | 1406.0889v1 |
2014-06-19 | Magnetic and Ising quantum phase transitions in a model for isoelectronically tuned iron pnictides | Considerations of the bad-metal behavior led to an early proposal for a
quantum critical point under a P for As doping in the iron pnictides, which has
since been experimentally observed. We study here an effective model for the
isoelectronically tuned pnictides using a large-$N$ approach. The model
contains antiferrom... | 1406.5136v2 |
2014-06-30 | Laboratories of Oligarchy? How the Iron Law Extends to Peer Production | Peer production projects like Wikipedia have inspired voluntary associations,
collectives, social movements, and scholars to embrace open online
collaboration as a model of democratic organization. However, many peer
production projects exhibit entrenched leadership and deep inequalities,
suggesting that they may not f... | 1407.0323v1 |
2014-07-05 | Nematic state stabilized by off-site Coulomb interaction in iron-based superconductors | Using a variational Monte Carlo method, we investigate the nematic state in
iron-base superconductors based on a three-band Hubbard model. Our results
demonstrate that the nematic state, formed by introducing an anisotropic
hopping order into the projected wave function, can arise in the underdoped
regime when a realis... | 1407.1411v1 |
2014-07-25 | Correlation, doping and interband effects on the optical conductivity of iron superconductors | Electronic interactions in multiorbital systems lead to non-trivial features
in the optical spectrum. In iron superconductors the Drude weight is strongly
suppressed with hole-doping. We discuss why the common association of the
renormalization of the Drude weight with that of the kinetic energy, used in
single band sy... | 1407.6935v2 |
2014-07-31 | Superconducting Gap and Symmetry in FeSe_1-x_Te_x_ Studied by Specific Heat in Magnetic Fields | In order to investigate details of the superconducting (SC) gap in the
iron-chalcogenide superconductors, the specific heat, C, of FeSe_1-x_Te_x_ with
x=0.6-1 has been measured in magnetic fields. Using the two-gap model, it has
been found that the smaller SC gap is significantly depressed by the
application of magneti... | 1407.8266v1 |
2014-08-01 | Charge-Stripe Order in a Parent Compound of Iron-based Superconductors | Charge ordering is one of the most intriguing and extensively studied
phenomena in correlated electronic materials because of its strong impact on
electron transport properties including superconductivity. Despite its
ubiquitousness in correlated systems, the occurrence of charge ordering in
iron-based superconductors ... | 1408.0057v1 |
2014-08-06 | Orbital Nematic Order and Interplay with Magnetism in the Two-Orbital Hubbard Model | Motivated by the recent angle-resolved photoemission spectroscopy (ARPES) on
FeSe and iron pnictide families of iron-based superconductors, we have studied
the orbital nematic order and its interplay with antiferromagnetism within the
two-orbital Hubbard model. We used random phase approximation (RPA) to
calculate the ... | 1408.1408v2 |
2014-08-27 | Tunable Band gap of Iron-Doped Lanthanum-Modified Bismuth Titanate Synthesized by the Thermal Decomposition of a Secondary Phase | The photoelectric properties of complex oxides have prompted interest in
materials with a tunable band gap, because the absorption The substitution of
iron atoms in La-modified bismuth titanate (BLT) can lead to dramatic
improvements in the band gap, however, the substitution of iron atoms in BLT
without forming a BiFe... | 1408.6294v1 |
2014-08-28 | Persistent detwinning of iron pnictides by small magnetic fields | Our comprehensive study on EuFe$_2$As$_2$ reveals a dramatic reduction of
magnetic detwinning fields compared to other AFe$_2$As$_2$ (A = Ba, Sr, Ca)
iron pnictides by indirect magneto-elastic coupling of the Eu$^{2+}$ ions. We
find that only 0.1T are sufficient for persistent detwinning below the local
Eu$^{2+}$ order... | 1408.6666v1 |
2014-09-05 | Electronic structure and Fermi surface of iron-based superconductors R2Fe3Si5 (R = Lu;Y;Sc) from first principles | Electronic structures of three superconducting rare-earth iron silicides
(Lu;Y;Sc)2Fe3Si5 and non-superconducting Lu2Ru3Si5, adopting a tetragonal
crystal structure (P4/mnc), have been calculated employing the full-potential
local-orbital method within the density functional theory. The investigations
were focused part... | 1409.1870v1 |
2014-09-17 | Depth of Maximum of Air-Shower Profiles at the Pierre Auger Observatory: Composition Implications | Using the data taken at the Pierre Auger Observatory between December 2004
and December 2012, we have examined the implications of the distributions of
depths of atmospheric shower maximum (Xmax), using a hybrid technique, for
composition and hadronic interaction models. We do this by fitting the
distributions with pre... | 1409.5083v1 |
2014-09-21 | Quantum oscillations and upper critical magnetic field of the iron-based superconductor FeSe | Shubnikov-de Haas (SdH) oscillations and upper critical magnetic field
($H\_{c2}$) of the iron-based superconductor FeSe ($T\_c$ = 8.6 K) have been
studied by tunnel diode oscillator-based measurements in magnetic fields of up
to 55 T and temperatures down to 1.6 K. Several Fourier components enter the
SdH oscillations... | 1409.6003v2 |
2014-10-03 | CuFeAs: A New Member in the 111-Family of Iron-Pnictides | We have synthesized CuFeAs, a new iron-pnictide compound with a layered
tetragonal Cu2Sb type structure (space group P4/nmm: a = b = 3.7442(2) {\AA}
and c = 5.8925(4) {\AA}) that is identical to that of 111-type iron-based
superconductors. Our measurements suggest that in low applied magnetic field it
undergoes an anti... | 1410.0805v1 |
2014-10-09 | Pair breaking due to orbital magnetism in iron-based superconductors | We consider superconductivity in the presence of impurities in a two-band
model suited for the description of iron-based superconductors. We analyze the
effect of interband scattering processes on superconductivity, allowing for
orbital, i.e., nonspin-magnetic but time-reversal symmetry-breaking impurities.
Pair breaki... | 1410.2555v2 |
2014-10-29 | Effective Exchange Interactions for Bad Metals and Implications for Iron-based Superconductors | The experimentally observed bad metal behavior in parent iron pnictides and
chalcogenides suggests that these systems contain strong electronic
correlations and are on the verge of a metal-to-insulator transition. The
magnetic excitations in this bad-metal regime mainly derive from the incoherent
part of the electronic... | 1410.8118v2 |
2014-10-30 | Spin-orbital interplay and topology in the nematic phase of iron pnictides | The origin of the nematic state is an important puzzle to be solved in iron
pnictides. Iron superconductors are multiorbital systems and these orbitals
play an important role at low energy. The singular $C_4$ symmetry of $d_{zx}$
and $d_{yz}$ orbitals has a profound influence at the Fermi surface since the
$\Gamma$ poc... | 1410.8488v4 |
2014-11-26 | Electronic and Magnetic Properties of the New Iron -- Based Superconductor [Li$_{1-x}$Fe$_x$OH]FeSe | We present the results of paramagnetic LDA band structure calculations: band
dispersions, densities of states and Fermi surfaces, for the new iron based
high-temperature superconductor LiOHFeSe. Main structural motif providing bands
in the vicinity of the Fermi level is FeSe layer which is isostructural to the
bulk FeS... | 1411.7194v1 |
2014-11-27 | The critical dynamics of the models of iron-vanadium magnetic superlattice | We report the results of a numerical investigation of static and dynamic
critical behavior of the anisotropic easy-plane Heisenberg model which is used
as a model for iron-vanadium magnetic superlattices. Models of iron-vanadium
magnetic superlattice investigated with different values of intralayer and
interlayer excha... | 1411.7509v1 |
2014-12-22 | Interplay between tetragonal magnetic order, stripe magnetism, and superconductivity in iron-based materials | Motivated by recent experiments in Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_{2}$ {[}A. E.
B\"ohmer \textit{et al}, to be published{]}, we analyze the type of
spin-density wave (SDW) order in doped iron-pnictides and the discontinuities
of the superconducting transition temperature $T_{c}$ in the coexistence phase
with SDW magnetis... | 1412.7079v2 |
2015-01-07 | Structure of superoxide reductase bound to ferrocyanide and active site expansion upon X-ray-induced photo-reduction | Some sulfate-reducing and microaerophilic bacteria rely on the enzyme
superoxide reductase (SOR) to eliminate the toxic superoxide anion radical
(O2*-). SOR catalyses the one-electron reduction of O2*- to hydrogen peroxide
at a nonheme ferrous iron center. The structures of Desulfoarculus baarsii SOR
(mutant E47A) alon... | 1501.01472v1 |
2015-01-29 | Link between local iron coordination, Fe 2p XPS core level line shape and Mg segregation into thin magnetite films grown on MgO(001) | A well ordered Fe(001) ultra thin film epitaxially grown on MgO(001) has been
oxidized by post deposition annealing in oxygen atmosphere. LEED patterns
indicate the formation of magnetite (Fe$_3$O$_4$) after one hour of oxygen
exposure. The LEED pattern remains stable despite annealing the sample for
further four hours... | 1501.07443v1 |
2015-02-04 | Disordered Fe vacancies and superconductivity in potassium-intercalated iron selenide (K2-xFe4+ySe5) | The parent compound of an unconventional superconductor must contain unusual
correlated electronic and magnetic properties of its own. In the high-Tc
potassium intercalated FeSe, there has been significant debate regarding what
the exact parent compound is. Our studies unambiguously show that the
Fe-vacancy ordered K2F... | 1502.01116v2 |
2015-02-09 | [NiFe] dithiolene diphosphine complex for hydrogen gas activation: a Theoretic Insight | A diphosphino-nickel-iron dithiolene complex, [Ni(bdt)(dppf)] (bdt =
1,2-benzenedithiolate, dppf = 1,1-bis(diphenylphosphino)ferrocene), has been
recently found to be reasonably active on proton reduction to dihydrogen (J.
Am. Chem. Soc. 2015, 137, 1109). Interestingly, this exceptional complex was
found to be also rea... | 1502.02706v1 |
2015-02-18 | Theoretical study on the correlation between the spin fluctuation and $T_c$ in the isovalent-doped 1111 iron-based superconductors | Motivated by recent experiments on isovalent-doped 1111 iron-based
superconductors LaFeAs$_{1-{x}}$P$_{x}$O$_{1-{y}}$F$_{y}$ and the theoretical
study that followed, we investigate, within the five orbital model, the
correlation between the spin fluctuation and the superconducting transition
temperature, which exhibits... | 1502.05144v1 |
2015-03-07 | The Three Dimensional Evolution to Core Collapse of a Massive Star | We present the first three dimensional (3D) simulation of the final minutes
of iron core growth in a massive star, up to and including the point of core
gravitational instability and collapse. We self-consistently capture the
development of strong convection driven by violent Si burning in the shell
surrounding the iro... | 1503.02199v2 |
2015-03-13 | Magnetic interactions in iron superconductors: A review | High temperature superconductivity in iron pnictides and chalcogenides
emerges when a magnetic phase is suppressed. The multi-orbital character and
the strength of correlations underlie this complex phenomenology, involving
magnetic softness and anisotropies, with Hund's coupling playing an important
role. We review he... | 1503.04223v2 |
2015-03-30 | Magnon contribution to the magnetoresistance of iron nanowires deposited using pulsed electrodeposition | Iron nanowires with a square cross section are grown by pulsed
electrodeposition within a newly developed nanochannel template that allows for
easy characterization. Measurements of the magnetoresistance as a function of
magnetic field and temperature are performed within a large parameter window
allowing for the inves... | 1503.08595v1 |
2015-04-17 | Nematic resonance in the Raman response of iron-based superconductors | In a fully-gapped superconductor the electronic Raman response has a
pair-breaking peak at twice the superconducting gap $\Delta$, if the Bogoliubov
excitations are uncorrelated. Motivated by the iron based superconductors, we
study how this peak is modified if the superconducting phase hosts a
nematic-structural quant... | 1504.04570v2 |
2015-05-03 | The Role of Temperature and Magnetic Effects on the Stacking-fault Energy in Austenitic Iron | We have investigated the role of temperature and magnetic effects on the
stacking-fault energy (SFE) in pure austenitic iron based on Density Functional
Theory (DFT) calculations. Using the axial next-nearest-neighbor Ising (ANNNI)
model, the SFE is expanded in terms of the free energiesof bulk with
face-centered cubic... | 1505.00431v2 |
2015-05-14 | Ab initio Studies of Magnetism in the Iron Chalcogenides FeTe and FeSe | The iron chalcogenides FeTe and FeSe belong to the family of iron-based
superconductors. We study the magnetism in these compounds in the normal state
using the ab initio downfolding scheme developed for strongly correlated
electron systems. In deriving ab initio low-energy effective models, we employ
the constrained G... | 1505.03730v2 |
2015-07-07 | The most iron-deficient stars as the polluted population III stars | We investigate the origin of the most iron-poor stars including SMSS
J031300.36-670839.3 with [Fe/H] < -7.52. We compute the change of surface
metallicity of stars with the accretion of interstellar matter (ISM) after
their birth using the chemical evolution model within the framework of the
hierarchical galaxy formati... | 1507.01664v1 |
2015-07-20 | Electronic nematic correlations in the stress free tetragonal state of BaFe$_{2-x}$Ni$_{x}$As$_{2}$ | We use transport and neutron scattering to study electronic, structural, and
magnetic properties of the electron-doped BaFe$_{2-x}$Ni$_x$As$_2$ iron
pnictides in the external stress free detwinned state. Using a specially
designed in-situ mechanical detwinning device, we demonstrate that the in-plane
resistivity anisot... | 1507.05423v1 |
2015-07-21 | Ab initio downfolding study of the iron-based ladder superconductor BaFe$_2$S$_3$ | Motivated by the recent discovery of superconductivity in the iron-based
ladder compound BaFe$_2$S$_3$ under high pressure, we derive low-energy
effective Hamiltonians from first principles. We show that the complex band
structure around the Fermi level is represented only by the Fe 3$d_{xz}$ (mixed
with 3$d_{xy}$) and... | 1507.05715v2 |
2015-07-22 | The Effects of Stoichiometry and Substitution in quasi-one-dimensional iron-chalcogenide BaFe$_{2}$S$_{3}$ | The effects of off-stoichiometry and elemental substitution on electronic
properties of iron-based ladder compound BaFe$_{2}$S$_{3}$ are investigated.
Resistivity and magnetization are revealed to be quite sensitive to the
stoichiometry of Fe atoms, and 10 \% deficiency at Fe sites reduces the
antiferromagnetic transit... | 1507.06047v1 |
2015-07-29 | Constraining planet structure from stellar chemistry: the cases of CoRoT-7, Kepler-10, and Kepler-93 | We explore the possibility that the stellar relative abundances of different
species can be used to constrain the bulk abundances of known transiting rocky
planets. We use high resolution spectra to derive stellar parameters and
chemical abundances for Fe, Si, Mg, O, and C in three stars hosting low mass,
rocky planets... | 1507.08081v1 |
2015-07-31 | Elastic Properties of FeC and FeN Martensites | Single crystal elastic constants of bcc iron and bct FeC and FeN alloys,
martensites, have been evaluated by ab initio calculations based on the density
functional theory. The energy of a strained crystal has been computed using the
supercell method at several values of the strain intensity, and the stiffness
coefficie... | 1508.00521v1 |
2015-08-17 | Spectroscopic Study of the Envelope of the Hybrid Nova V458 Vul and Surrounding Nebula | Spectroscopic observations of the hybrid V458 Vul obtained between days 9 and
778 after the brightness maximum are analyzed. Short-period, daily profile
variations of forbidden [FeVII] iron lines were detected in the nebular phase,
as well as a long-period (about 60-day) cyclic variation that was correlated
with the ph... | 1508.03990v1 |
2015-11-16 | Tracing the $s_\pm$-symmetry in iron pnictides by controlled disorder | Consecutive proton irradiation of iron pnictides reduces the superconducting
transition temperature to decrease monotonically. Our systematic optical THz
investigations of Ba(Fe$_{0.9}$Co$_{0.1}$)$_2$As$_2$ thin films reveal,
however, that the low-energy superconducting gap is first suppressed, but
recovers for higher ... | 1511.05017v2 |
2015-11-20 | Impact of ordering competition on the global phase diagram of iron pnictides | We consider the impact of the competition among superconductivity, spin
density wave, and nematic order in iron pnictides, and show that the ordering
competition substantially reshapes the global phase diagram. We perform a
detailed renormalization group analysis of an effective field theory of iron
pnictides and deriv... | 1511.06517v1 |
2015-11-24 | Nodal superconductivity in FeS: Evidence from quasiparticle heat transport | We report low-temperature heat transport measurements on superconducting iron
sulfide FeS with $T_c \approx$ 5 K, which has the same crystal structure and
similar electronic band structure to the superconducting iron selenide FeSe. In
zero magnetic field, a significant residual linear term $\kappa_0/T$ is
observed. At ... | 1511.07717v3 |
2016-01-13 | Hybrid Crystals of Cuprates and Iron-Based Superconductors | We propose two possible new compounds, Ba$_2$CuO$_2$Fe$_2$As$_2$ and
K$_2$CuO$_2$Fe$_2$Se$_2$, which hybridize the building blocks of two high
temperature superconductors, cuprates and iron-based superconductors. These
compounds consist of square CuO$_2$ layers and antifluorite-type Fe$_2$X$_2$
(X=As,Se) layers separat... | 1601.03220v1 |
2016-01-28 | Effects of Pnictogen Atmosphere Annealing in Fe$_{1+y}$Te$_{0.6}$Se$_{0.4}$ | It has been clarified that bulk superconductivity in
Fe$_{1+y}$Te$_{0.6}$Se$_{0.4}$ can be induced by annealing in an appropriate
atmosphere to remove the harmful effects of excess iron. In order to clarify
the details of the annealing process, we studied the changes in the physical
properties and reaction products of ... | 1601.07703v1 |
2016-02-16 | Orbital selectivity of layer resolved tunneling on iron superconductor Ba0.6K0.4Fe2As2 | We use scanning tunneling microscopy/spectroscopy (STM/S) to elucidate the
Cooper pairing of the iron pnictide superconductor Ba0.6K0.4Fe2As2. By a
cold-cleaving technique, we obtain atomically resolved termination surfaces
with different layer identities. Remarkably, we observe that the low-energy
tunneling spectrum r... | 1602.04949v2 |
2016-02-16 | Extreme abundance ratios in the polluted atmosphere of the cool white dwarf NLTT19868 | We present an analysis of intermediate-dispersion spectra and photometric
data of the newly identified cool, polluted white dwarf NLTT19868. The spectra
obtained with X-shooter on the Very Large Telescope (VLT)-Melipal show strong
lines of calcium, and several lines of magnesium, aluminium and iron. We use
these spectr... | 1602.05000v1 |
2016-02-17 | Magnetism, superconductivity, and spontaneous orbital order in iron-based superconductors: who comes first and why? | Magnetism and nematic order are the two non-superconducting orders observed
in iron-based superconductors. To elucidate the interplay between them and
ultimately unveil the pairing mechanism, several models have been investigated.
In models with quenched orbital degrees of freedom, magnetic fluctuations
promote stripe ... | 1602.05503v1 |
2016-03-05 | Phase transitions in a frustrated biquadratic Heisenberg model with coupled orbital degree of freedom for iron-based superconductors | In this work, we study a biquadratic Heisenberg model with coupled orbital
degree of freedom using Monte Carlo simulation in order to investigate the
phase transitions in iron-based superconductors. The antiferro-quadrupolar
state, which may be related to the magnetism of FeSe [Phys. Rev. Lett. 115,
116401 (2015)], is ... | 1603.01669v1 |
2016-03-10 | Spin and quadrupolar orders in the spin-1 bilinear-biquadratic model for iron-based superconductors | Motivated by recent experimental and theoretical progresses of the magnetic
properties of iron-based superconductors, we provide a comprehensive analysis
of the spin-1 bilinear-biquadratic (BBQ) model on the square lattice. Using
variational approach in the mean-field level, we identify the existence of
various magneti... | 1603.03273v2 |
2016-03-14 | A study for testing the Kerr metric with AGN iron line eclipses | Recently, two of us have studied iron line reverberation mapping to test
black hole candidates, showing that the time information in reverberation
mapping can better constrain the Kerr metric than the time-integrated approach.
Motivated by this finding, here we explore the constraining power of another
time-dependent m... | 1603.04115v2 |
2016-03-15 | Testing the Kerr black hole hypothesis: comparison between the gravitational wave and the iron line approaches | The recent announcement of the detection of gravitational waves by the
LIGO/Virgo collaboration has opened a new window to test the nature of
astrophysical black holes. Konoplya & Zhidenko have shown how the LIGO data of
GW 150914 can constrain possible deviations from the Kerr metric. In this
letter, we compare their ... | 1603.04720v2 |
2016-04-12 | High Temperature Superconductivity in Iron Pnictides and Chalcogenides | Superconductivity develops in metals upon the formation of a coherent
macroscopic quantum state of electron pairs. Iron pnictides and chalcogenides
are materials that have high superconducting transition temperatures. In this
Review, we describe the advances in the field that have led to higher
superconducting transiti... | 1604.03566v1 |
2016-04-24 | Vanishing Absorption and Blueshifted Emission in FeLoBAL Quasars | We study the dramatic decrease in iron absorption strength in the iron
low-ionization broad absorption line quasar SDSS J084133.15+200525.8. We report
on the continued weakening of absorption in the prototype of this class of
variable broad absorption line quasar, FBQS J140806.2+305448. We also report a
third example o... | 1604.06977v1 |
2016-05-09 | A global look at X-ray time lags in Seyfert Galaxies | X-ray reverberation, where light-travel time delays map out the compact
geometry around the inner accretion flow in supermassive black holes, has been
discovered in several of the brightest, most variable and well-known Seyfert
galaxies. In this work, we expand the study of X-ray reverberation to all
Seyfert galaxies i... | 1605.02631v1 |
2016-05-31 | Thermoelectric properties of iron-based superconductors and parent compounds | Herewith, we review the available experimental data of thermoelectric
transport properties of iron-based superconductors and parent compounds. We
discuss possible physical mechanisms into play in determining the Seebeck
effect, from whence one can extract information about Fermi surface
reconstruction and Lifshitz tran... | 1605.09577v1 |
2016-06-03 | Synthesis, phase stability, structural and physical properties of 11-type iron chalcogenides | This article reviews recent experimental investigations on two binary
Fe-chalcogenides: FeSe and Fe$_{1+y}$Te. The main focus is on synthesis, single
crystal growth, chemical composition, as well as on the effect of excess iron
on structural, magnetic, and transport properties of these materials. The
structurally simpl... | 1606.01012v1 |
2016-06-05 | Enhanced critical-current in P-doped BaFe2As2 thin films on metal substrates arising from poorly aligned grain boundaries | Thin films of the iron-based superconductor BaFe2(As1-xPx)2 (Ba122:P) were
fabricated on polycrystalline metal-tape substrates with two kinds of in-plane
grain boundary alignments (well aligned (4 deg.) and poorly aligned (8 deg.))
by pulsed laser deposition. The poorly aligned substrate is not applicable to
cuprate-co... | 1606.01477v2 |
2016-07-09 | Orientation of the electric field gradient and ellipticity of the magnetic cycloid in multiferroic BiFeO3 | The paper deals with the hyperfine interactions observed on the 57Fe nucleus
in multiferroic BiFeO3 by means of the 14.41-keV resonant transition in 57Fe,
and for transmission geometry applied to the random powder sample. Spectra were
obtained at 80 K, 190 K and at room temperature. It was found that iron occurs
in the... | 1607.02601v3 |
2016-07-11 | An Iron K Component to the Ultrafast Outflow in NGC 1313 X-1 | We present the detection of an absorpton feature at $E=8.77^{+0.05}_{-0.06}$
keV in the combined X-ray spectrum of the ultraluminous X-ray source NGC 1313
X-1 observed with XMM-Newton and NuSTAR, significant at the 3$\sigma$ level. If
associated with blueshifted ionized iron, the implied outflow velocity is
~0.2$c$ for... | 1607.03124v1 |
2016-07-19 | Relativistic iron lines in accretion disks: the contribution of higher order images in the strong deflection limit | The shapes of relativistic iron lines observed in spectra of candidate black
holes carry the signatures of the strong gravitational fields in which the
accretion disks lie. These lines result from the sum of the contributions of
all images of the disk created by gravitational lensing, with the direct and
first-order im... | 1607.05365v2 |
2016-07-19 | Spin resonance in the superconducting state of Li$_{1-x}$Fe$_{x}$ODFe$_{1-y}$Se observed by neutron spectroscopy | We have performed inelastic neutron scattering measurements on a powder
sample of the superconductor lithium iron selenide hydroxide
Li$_{1-x}$Fe$_{x}$ODFe$_{1-y}$Se ($x \simeq 0.16, y \simeq 0.02$, $T_{\rm c} =
41$\,K). The spectrum shows an enhanced intensity below $T_{\rm c}$ over an
energy range $0.64\times2\Delta ... | 1607.05588v2 |
2016-07-19 | Synthesis of strontium ferrite/iron oxide exchange coupled nano-powders with improved energy product for rare earth free permanent magnet applications | We present a simple, scalable synthesis route for producing exchange coupled
soft/hard magnetic composite powder that outperforms pure soft and hard phase
constituents. Importantly, the composites is iron oxide based (SrFe12O19 and
Fe3O4) and contain no rare earth or precious metal. The two step synthesis
process consi... | 1607.05689v1 |
2016-08-11 | Collective magnetic excitations of $C_{4}$ symmetric magnetic states in iron-based superconductors | We study the collective magnetic excitations of the recently discovered
$C_{4}$ symmetric spin-density wave states of iron-based superconductors with
particular emphasis on their orbital character based on an itinerant
multiorbital approach. This is important since the $C_{4}$ symmetric
spin-density wave states exist o... | 1608.03493v1 |
2016-11-08 | Superconductivity and magnetism in Iron Sulfides Intercalated by Metal Hydroxides | Inspired by naturally occurring sulfide minerals, we present a new family of
iron-based superconductors. A metastable form of FeS known as the mineral
mackinawite forms two-dimensional sheets that can be readily intercalated by
various cationic guest species. Under hydrothermal conditions using alkali
metal hydroxides,... | 1611.02383v2 |
2016-11-11 | Antiferromagnetic order in epitaxial FeSe films on SrTiO3 | Single monolayer FeSe film grown on Nb-doped SrTiO$_3$(001) substrate shows
the highest superconducting transition temperature (T$_C$ $\sim$ 100 K) among
the iron-based superconductors (iron-pnictide), while T$_C$ of bulk FeSe is
only $\sim$ 8 K. Antiferromagnetic spin fluctuations were believed to be
crucial in iron-p... | 1611.03603v2 |
2016-12-30 | Exchange Bias Effects in Iron Oxide-Based Nanoparticle Systems | The exploration of exchange bias (EB) on the nanoscale provides a novel
approach to improving the anisotropic properties of magnetic nanoparticles for
prospective applications in nanospintronics and nanomedicine. However, the
physical origin of EB is not fully understood. Recent advances in chemical
synthesis provide a... | 1612.09455v1 |
2017-01-10 | Size-dependent frequency bands in the ferromagnetic resonance of a Fe-nanocube | Using full micromagnetic simulations we calculate the spectra of
ferromagnetic resonance (FMR) for an iron (core-shell) nanocube and show that
the FMR characteristics are strongly size dependent. For instance, for a
$40~$nm it is found that, in contrast to a macrospin picture, the spectrum of
the iron nanocube possesse... | 1701.02503v1 |
2017-02-08 | Magnetic Lifshitz transition and its consequences in multi-band iron-based superconductors | In this paper we address Lifshitz transition induced by applied external
magnetic field in a case of iron-based superconductors, in which a difference
between the Fermi level and the edges of the bands is relatively small. We
introduce and investigate a two-band model with intra-band pairing in the
relevant parameters ... | 1702.02612v1 |
2017-03-13 | Various arsenic network structures in 112-type Ca1-xLaxFe1-yPdyAs2 revealed by synchrotron x-ray diffraction experiments | Two novel 112-type palladium doped iron arsenides were synthesized and
identified using comprehensive studies involving synchrotron x-ray diffraction
and x-ray absorption near edge structure (XANES) experiments. Whereas in-plane
arsenic zigzag chains were found in 112-type superconducting iron arsenide,
Ca1-xLaxFeAs2 w... | 1703.04204v1 |
2017-04-07 | Spin wave propagation and spin polarized electron transport in single crystal iron films | The technique of propagating spin wave spectroscopy is applied to a 20 nm
thick Fe/MgO (001) film. The magnetic parameters extracted from the position of
the resonance peaks are very close to those tabulated for bulk iron. From the
propagating waveforms, a group velocity of 4 km/s and an attenuation length of
about 6 m... | 1704.02217v1 |
2017-04-11 | Possible Bicollinear Nematic State with Monoclinic Lattice Distortions in Iron Telluride Compounds | Iron telluride FeTe is known to display bicollinear magnetic order at low
temperatures together with a monoclinic lattice distortion. Because the
bicollinear order can involve two different wavevectors $(\pi/2,\pi/2)$ and
$(\pi/2,-\pi/2)$, symmetry considerations allow for the possible stabilization
of a nematic state ... | 1704.03495v2 |
2017-04-28 | Strong anisotropy effect in iron-based superconductor CaFe$_{0.882}$Co$_{0.118}$AsF | The anisotropy of the Fe-based superconductors is much smaller than that of
the cuprates and the theoretical calculations. A credible understanding for
this experimental fact is still lacking up to now. Here we experimentally study
the magnetic-field-angle dependence of electronic resistivity in the
superconducting pha... | 1704.08791v1 |
2017-05-31 | Crystal growth and phase diagram of 112-type iron pnictide superconductor Ca1-yLayFe1-xNixAs2 | We report a systematic crystal growth and characterization of
Ca$_{1-y}$La$_{y}$Fe$_{1-x}$Ni$_{x}$As$_{2}$, the newly discovered 112-type
iron-based superconductor. After substituting Fe by a small amount of Ni, bulk
superconductivity is successfully obtained in high quality single crystals
sized up to 6 mm. Resistivit... | 1705.11144v1 |
2017-06-06 | Detailed opacity calculations for astrophysical applications | Nowadays, several opacity codes are able to provide data for stellar
structure models, but the computed opacities may show significant differences.
In this work, we present state-of-the-art precise spectral opacity
calculations, illustrated by stellar applications. The essential role of
laboratory experiments to check ... | 1706.01761v1 |
2017-06-10 | Local orthorhombicity in the magnetic $C_4$ phase of the hole-doped iron-arsenide superconductor Sr$_{1-x}$Na$_{x}$Fe$_2$As$_2$ | We report temperature-dependent pair distribution function measurements of
Sr$_{1-x}$Na$_{x}$Fe$_2$As$_2$, an iron-based superconductor system that
contains a magnetic phase with reentrant tetragonal symmetry, known as the
magnetic $C_4$ phase. Quantitative refinements indicate that the instantaneous
local structure in... | 1706.03279v2 |
2017-06-16 | Observation of topological superconductivity on the surface of an iron-based superconductor | Topological superconductors, whose edge hosts Majorana bound states or
Majorana fermions that obey non-Abelian statistics, can be used for
low-decoherence quantum computations. Most of the proposed topological
superconductors are realized with spin-helical states through proximity effect
to BCS superconductors. However... | 1706.05163v2 |
2017-06-23 | Dynamic Simulation of Structural Phase Transitions in Magnetic Iron | The occurrence of bcc-fcc ($\alpha$-$\gamma$) and fcc-bcc ($\gamma$-$\delta$)
phase transitions in magnetic iron stems from the interplay between magnetic
excitations and lattice vibrations. However, this fact has never been proven by
a direct dynamic simulation, treating non-collinear magnetic fluctuations and
dynamic... | 1706.07635v1 |
2017-07-12 | Local magnetic moments in iron and nickel at ambient and Earth's core conditions | Some Bravais lattices have a particular geometry that can slow down the
motion of Bloch electrons by pre-localization due to the band-structure
properties. Another known source of electronic localization in solids is the
Coulomb repulsion in partially filled d- or f-orbitals, which leads to the
formation of local magne... | 1707.03789v1 |
2017-07-19 | On local sensing of spin Hall effect in tungsten films by using STM-based measurements | The spin Hall effect in tungsten films has been experimentally studied by
using STM-based measurements. These measurements have been performed by using
tungsten and iron coated tungsten tips. In the case of tungsten tips, it has
been observed that the current flow through the tungsten film results in an
appreciable asy... | 1707.06116v2 |
2017-09-18 | Magnetism and superconductivity in the layered hexagonal transition metal pnictides | We investigate the electronic and magnetic structures of the 122
(AM$_2$B$_2$) hexagonal transition-metal pnictides with A=(Sr, Ca), M=(Cr, Mn,
Fe, Co, Ni) and B=(As, P, Sb). It is found that the family of materials share
critical similarities with those of tetragonal structures that include the
famous iron-based high ... | 1709.05736v1 |
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