publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2017-10-30 | X-ray reflection from the inner disk of the AGN Ton S180 | We analyse a long archival XMM-Newton observation of the narrow-line Seyfert
1 galaxy Ton S180, using the latest reflection models to explore the high
quality X-ray spectrum. We find that the iron line is relatively narrow and
sharp, and the soft excess is extremely smooth. We cannot find an acceptable
reflection model... | 1710.11166v1 |
2017-11-08 | Effect of density of states peculiarities on Hund's metal behavior | We investigate a possibility of Hund's metal behavior in the Hubbard model
with asymmetric density of states having peak(s). Specifically, we consider the
degenerate two-band model and compare its results to the five-band model with
realistic density of states of iron and nickel, showing that the obtained
results are m... | 1711.02991v3 |
2017-11-15 | Phase-sensitive evidence for the sign-reversal s+- symmetry of the order parameter in an iron-pnictide superconductor using Nb/Ba1-xNaxFe2As2 Josephson junctions | Josephson current between two superconductors provides a phase sensitive tool
for probing their pairing symmetries. Here we fabricate and study
experimentally high-quality Josephson junctions between a conventional s-wave
superconductor Nb and a multi-band iron-pnictide Ba$_{1-x}$Na$_x$Fe$_2$As$_2$.
Junctions exhibit a... | 1711.05718v2 |
2017-11-17 | Nematicity, magnetism and superconductivity in FeSe | Iron-based superconductors are well known for their complex interplay between
structure, magnetism and superconductivity. FeSe offers a particularly
fascinating example. This material has been intensely discussed because of its
extended nematic phase, whose relationship with magnetism is not obvious.
Superconductivity ... | 1711.06473v1 |
2017-11-28 | Doping evolution of the anisotropic upper critical fields in iron-based superconductor Ba$_{1-x}$K$_x$Fe$_2$As$_2$ | In-plane resistivity measurements as a function of temperature and magnetic
field up to 35~T with precise orientation within the crystallographic
$ac-$plane were used to study the upper critical field, $H_{c2}$, of the
hole-doped iron-based superconductor Ba$_{1-x}$K$_x$Fe$_2$As$_2$. Compositions
of the samples studied... | 1711.10094v1 |
2017-11-30 | Iron superhydrides FeH5 and FeH6: stability, electronic properties and superconductivity | Recently a big number of works devoted to search for new hydrides with record
high-temperature superconductivity and at the same time the successful
synthesis of potential high-TC superconducting FeH5 was reported. We present a
systematic search for stable compounds in the Fe-H system using
variable-composition version... | 1711.11352v3 |
2017-12-12 | Substitution- and Strain-induced Magnetic Phase Transition in Iron Carbide | Cementite-type carbides are of interest for magnetocaloric applications owing
to their temperature- or pressure-induced magnetic phase transition. Here,
using first-principles calculations, we investigate the magnetism and the
magnetic phase transition in iron carbide (Fe3C) with the substitution of Cr
atoms at Fe site... | 1712.04128v1 |
2017-12-12 | In situ annealing effects on the iron-based ladder material BaFe_2S_3: A route to improve the crystal quality | We have grown single crystals of the iron-based ladder material BaFe_2S_3,
which is superconductive under high pressure, adopting different conditions. By
comparing the behaviors of these samples, it is found that the in situ
annealing process can affect the crystal structure and the electrical
transport, enhance the a... | 1712.04241v1 |
2017-12-25 | Magnon and Phonon Dispersion, Lifetime and Thermal Conductivity of Iron from Spin-Lattice Dynamics Simulations | In recent years, the fundamental physics of spin-thermal (i.e.,
magnon-phonon) interaction has attracted significant experimental and
theoretical interests given its potential paradigm-shifting impacts in areas
like spin-thermoelectrics, spin-caloritronics and spintronics. Modelling
studies of the transport of magnons ... | 1712.09002v1 |
2017-12-31 | Magnetic and Structural Properties of the Iron Oxychalcogenides La$_{2}$O$_{2}$Fe$_{2}$O$M_{2}$ ($M$= S, Se) | We present the results of structural and magnetic phase comparisons of the
iron oxychalcogenides La$_{2}$O$_{2}$Fe$_{2}$O$M$$_{2}$ ($M$ = S, Se). Elastic
neutron scattering reveals that $M$ = S and Se have similar nuclear structures
at room and low temperatures. We find that both materials obtain
antiferromagnetic orde... | 1801.00342v2 |
2018-01-03 | Structures and magnetic properties of iron silicide from adaptive genetic algorithm and first-principles calculations | We performed a systematic search for low-energy structures of binary iron
silicide over a wide range of compositions using the crystal structure
prediction method based on adaptive genetic algorithm. 36 structures with
formation energies within 50 meV/atom (11 of them are within 20 meV) above the
convex hull formed by ... | 1801.01004v1 |
2018-01-15 | Testing exterior spacetime of the neutron star via X-ray reflection spectroscopy | The exterior geometry of a neutron star can be approximated by relativistic
multipole moments of a parametrized metric using Ernst potential formalism.
This spacetime can be tested with electromagnetic wave observation of
astrophysical black holes. In the present paper, I simulate X-ray reflection
spectra of a thin acc... | 1801.04657v2 |
2018-01-19 | Spectral analysis of the He-enriched sdO-star HD 127493 | The bright sdO star HD 127493 is known to be of mixed H/He composition and
excellent archival spectra covering both optical and ultraviolet ranges are
available. UV spectra play a key role as they give access to many chemical
species that do not show spectral lines in the optical, such as iron and
nickel. This encourag... | 1801.06350v1 |
2018-01-31 | Detection of bosonic mode as a signature of magnetic excitation in one unit cell FeSe on SrTiO3 | We report an in situ scanning tunneling spectroscopy study of one-unit-cell
(1-UC) FeSe film on SrTiO3(001) (STO) substrate. In quasiparticle density of
states, bosonic excitation mode characterized by the "dip-hump" structure is
detected outside the larger superconducting gap with energy comparable with
phonon and spi... | 1801.10363v2 |
2018-02-08 | Direct observation of spin excitation anisotropy in the paramagnetic orthorhombic state of BaFe$_{2-x}$Ni$_x$As$_2$ | We use transport and inelastic neutron scattering measurements to investigate
single crystals of iron pnictide BaFe$_{2-x}$Ni$_{x}$As$_{2}$ ($x=0,0.03$),
which exhibit a tetragonal-to-orthorhombic structural transition at $T_s$ and
stripe antiferromagnetic order at $T_N$ ($T_s\geq T_N$).
Using a tunable uniaxial pres... | 1802.02713v1 |
2018-02-20 | Magnetic exchange and susceptibilities in fcc iron: A supercell dynamical mean-field theory study | We study the momentum- and temperature dependencies of magnetic
susceptibilities and magnetic exchange in paramagnetic fcc iron by a
combination of density functional theory and supercell dynamical mean-field
theory (DFT+DMFT). We find that in agreement with experimental results the
antiferromagnetic correlations with ... | 1802.07061v2 |
2018-03-01 | Hydrogen embrittlement controlled by reaction of dislocation with grain boundary in alpha-iron | Hydrogen atoms absorbed by metals in the hydrogen-containing environments can
lead to the premature fracture of the metal components used in load-bearing
conditions. Since metals used in practice are mostly polycrystalline, grain
boundaries (GBs) can play an important role in hydrogen embrittlement of
metals. Here we s... | 1803.00287v2 |
2018-03-06 | Combined Molecular and Spin Dynamics Simulation of BCC Iron with Vacancy Defects | Utilizing an atomistic computational model which handles both translational
and spin degrees of freedom, combined molecular and spin dynamics simulations
have been performed to investigate the effect of vacancy defects on spin wave
excitations in ferromagnetic iron. Fourier transforms of space and
time-displaced correl... | 1803.02468v1 |
2018-03-07 | Antiphase Fermi-surface modulations accompanying displacement excitation in a parent compound of iron-based superconductors | We investigate the transient electronic structure of BaFe2As2, a parent
compound of iron-based superconductors, by time- and angle-resolved
photoemission spectroscopy. In order to probe the entire Brillouin zone, we
utilize extreme ultraviolet photons and observe photoemission intensity
oscillation with the frequency o... | 1803.02599v1 |
2018-03-07 | New Experimental Limits on Exotic Spin-Spin-Velocity-Dependent Interactions By Using SmCo$_5$ Spin Sources | We report the latest results of searching for possible new macro-scale
spin-spin-velocity-dependent forces (SSVDFs) based on specially designed
iron-shielded SmCo$_5$ (ISSC) spin sources and a spin exchange relaxation free
(SERF) co-magnetometer. The ISSCs have high net electron spin densities of
about $1.7\times 10^{2... | 1803.02813v2 |
2018-03-15 | Nodal-to-nodeless superconducting order parameter in LaFeAs$_{1-x}$P$_x$O synthesized under high pressure | Similar to chemical doping, pressure produces and stabilizes new phases of
known materials, whose properties may differ greatly from those of their
standard counterparts. Here, by considering a series of LaFeAs$_{1-x}$P$_x$O
iron-pnictides synthesized under high-pressure high-temperature conditions, we
investigate the ... | 1803.05733v1 |
2018-03-22 | On the performance of interatomic potential models of iron: comparison of the phase diagrams | In order to study the performance of interatomic potentials and their
reliability at higher pressures, the phase diagram of four different
embedded-atom type potential models of iron is compared. The calculations were
done by the nested sampling technique in the pressure range 0.1 GPa-100 GPa.
The low pressure stable s... | 1803.08400v1 |
2018-03-27 | Oxygen and zinc abundances in 417 Galactic bulge red giants | Oxygen and zinc in the Galactic bulge are key elements for the understanding
of the bulge chemical evolution. Oxygen-to-iron abundance ratios provide a most
robust indicator of the star formation rate and chemical evolution of the
bulge. Zinc is enhanced in metal-poor stars, behaving as an $\alpha$-element,
and its pro... | 1803.09942v1 |
2018-04-10 | The Dark Side of the Sun A Plea for a Next-Generation Opacity Calculation | Is the Sun likely to have a more opaque interior than previously thought? The
solar oxygen (or abundance) problem can be solved with higher interior
opacities, reconciling abundance analyses based on 3D convective atmospheres
with the helioseismic structure of the solar interior. This has been known for
more than a dec... | 1804.03746v1 |
2018-04-16 | Ultrafast destruction and recovery of the spin density wave order in iron based pnictides: a multi-pulse optical study | We report on systematic excitation-density dependent all-optical femtosecond
time resolved study of the spin-density wave state in iron-based
superconductors. The destruction and recovery dynamics are measured by means of
the standard and a multi-pulse pump-probe technique. The experimental data are
analyzed and interp... | 1804.05769v1 |
2018-04-25 | Magnon thermal Hall effect in kagome antiferromagnets with Dzyaloshinskii-Moriya interactions | We theoretically study magnetic and topological properties of
antiferromagnetic kagome spin systems in the presence of both in- and
out-of-plane Dzyaloshinskii-Moriya interactions. In materials such as the iron
jarosites, the in-plane interactions stabilize a canted noncollinear "umbrella"
magnetic configuration with f... | 1804.09783v2 |
2018-04-26 | TRAPPIST-1e Has a Large Iron Core | The TRAPPIST-1 system provides an exquisite laboratory for understanding
exoplanetary atmospheres and interiors. Their mutual gravitational interactions
leads to transit timing variations, from which Grimm et al. (2018) recently
measured the planetary masses with precisions ranging from 5% to 12%. Using
these masses an... | 1804.10618v1 |
2018-05-07 | Nebular spectroscopy of SN 2014J: Detection of stable nickel in near infrared spectra | We present near infrared (NIR) spectroscopy of the nearby supernova 2014J
obtained $\sim$450 d after explosion. We detect the [Ni II] 1.939 $\mu$m line
in the spectra indicating the presence of stable $^{58}$Ni in the ejecta. The
stable nickel is not centrally concentrated but rather distributed as the iron.
The spectr... | 1805.02420v1 |
2018-05-17 | Exploring the spectral variability of the Seyfert 1.5 galaxy Markarian 530 with Suzaku | A 2012 Suzaku observation of the Seyfert 1.5 galaxy Markarian 530 was
analysed and found to exhibit two distinct modes of variability, which were
found to be independent from one another. Firstly, the spectrum undergoes a
smooth transition from a soft to a hard spectrum. Secondly, the spectrum
displays more rapid varia... | 1805.06742v1 |
2018-05-24 | Quasi-one Dimensional Nanostructures as Sign of Nematicity in Iron Pnictides and Chalcogenides | Impurity scattering is found to lead to quasi-one dimensional nanoscale
modulation of the local density of states in the iron pnictides and
chalcogenides. This `quasiparticle interference' feature is remarkably similar
across a wide variety of pnictide and chalcogenide phases, suggesting a common
origin. We show that a... | 1805.09582v2 |
2018-05-28 | Friction and friction heat of micronscale iron | The paper investigates friction and friction heat of the micronscale iron
under influences of velocity of the slider and temperature of the substrate by
using smoothed particle hydrodynamics simulations. In the velocity range of 10
- 100 m/s, change of friction coefficient via velocity well complies with
exponent or hy... | 1805.10781v1 |
2018-05-29 | Trends in pressure-induced layer-selective half-collapsed tetragonal phases in the iron-based superconductor family $Ae{}A$Fe$_4$As$_4$ | By performing pressure simulations within density functional theory for the
family of iron-based superconductors $Ae{}A$Fe$_4$As$_4$ with $Ae$ = Ca, Sr, Ba
and $A$ = K, Rb, Cs we predict in these systems the appearance of two
consecutive half-collapsed tetragonal transitions at pressures $P_{c_1}$ and
$P_{c_2}$, which ... | 1805.11409v1 |
2018-06-01 | Two-stage three-channel Kondo physics for an FePc molecule on the Au(111) surface | We study an impurity Anderson model to describe an iron phthalocyanine (FePc)
molecule on Au(111), motivated by previous results of scanning tunneling
spectroscopy (STS) and theoretical studies. The model hybridizes a spin doublet
consisting in one hole at the $3d_{z^2}$ orbital of iron and two degenerate
doublets corr... | 1806.00402v1 |
2018-06-04 | Pressure tuned superconductivity and normal state behavior in Ba(Fe$_{0.943}$Co$_{0.057}$)$_2$As$_2$ near the antiferromagnetic boundary | Superconductivity in iron pnictides is unconventional and pairing may be
mediated by magnetic fluctuations in the Fe-sublattice. Pressure is a clean
method to explore superconductivity in iron based superconductors by tuning the
ground state continuously without introducing disorder. Here we present a
systematic high p... | 1806.01432v1 |
2018-06-06 | Effect of electron correlations on spin excitation bandwidth in Ba$_{0.75}$K$_{0.25}$Fe$_{2}$As$_{2}$ as seen via time-of-flight inelastic neutron scattering | We use inelastic neutron scattering (INS) to investigate the effect of
electron correlations on spin dynamics in the iron-based superconductor
Ba$_{0.75}$K$_{0.25}$Fe$_{2}$As$_{2}$. Our INS data show a spin-wave-like
dispersive feature, with a zone boundary energy of 200 meV. A first principles
analysis of dynamical sp... | 1806.02097v1 |
2018-06-23 | The driving mechanism of the d-wave orbital order in the iron-based superconductors | We study the driving mechanism and the form of the orbital order in the
electronic nematic phase of the iron-based superconductors(IBSs) within the
random phase approximation of a 5-band model. We find the magnetic correlation
energy of the system can be significantly improved when an orbital order of the
d-wave form i... | 1806.08907v1 |
2018-07-05 | Probing Charge Transfer Dynamics in a Single Iron Tetraphenylporphyrin Dyad Adsorbed on an Insulating Surface | Although the dynamics of charge transfer (CT) processes can be probed with
ultimate lifetime resolution, the helplessness to control CT at the nanoscale
constitutes one of the most important road-blocks to revealing some of its deep
fundamental aspects. In this work, we present an investigation of CT dynamics
in a sing... | 1807.01876v1 |
2018-07-28 | Stability and magnetism of FeN high-pressure phases | Experimentally discovered compounds in the iron-nitrogen system belong to the
low concentration part of the Fe-N phase diagram. In our paper, which is based
on ab initio calculations we have studied formation and stability of
high-pressure iron mono-nitride phases, and particularly the new magnetic phase
with a NiAs-ty... | 1807.10874v2 |
2018-08-01 | Disruption of a planet spiralling into its host star | The processes leading deformation and destruction of planets spiraling into
the convective envelope of their host stars are described. The planet is
compressed by the ram pressure, and deformed into a flattened shape for which a
quantitative model is developed. Compression increases the planet's density
contrast with t... | 1808.00467v1 |
2018-08-17 | Cepheid Abundances: Multiphase Results and Spatial Gradients | Parameters and abundances have been derived for 435 Cepheids based on an
analysis of 1127 spectra. Results from five or more phases are available for 52
of the program stars. The latter set of stars span periods between 1.5 and 68
days. The parameters and abundances show excellent consistency across phase.
For iron, th... | 1808.05863v1 |
2018-09-03 | On the relationship between metallicity distributions of globular clusters and of circumgalactic gas | The abundance of alpha elements and iron in stars of globular clusters shows
the composition of the gaseous medium, in which they have been formed. In the
present paper, we discuss a possibility to consider dense clouds of
circumgalactic gas (partial Lyman limit systems and Lyman limit systems)
observed in the 100 - 13... | 1809.00621v2 |
2018-09-05 | Widespread orthorhombic fluctuations in the (Sr,Na)Fe$_2$As$_2$ family of superconductors | We report comprehensive pair distribution function measurements of the
hole-doped iron-based superconductor system Sr$_{1-x}$Na$_{x}$Fe$_2$As$_2$.
Structural refinements performed as a function of temperature and length scale
reveal orthorhombic distortions of the instantaneous local structure across a
large region of ... | 1809.01764v2 |
2018-09-21 | Crystal Structures and Properties of Iron Hydrides at High Pressure | Evolutionary algorithms and the particle swarm optimization method have been
used to predict stable and metastable high hydrides of iron between 150-300 GPa
that have not been discussed in previous studies. Cmca FeH5, Pmma FeH6 and P2/c
FeH6 contain hydrogenic lattices that result from slight distortions of the
previou... | 1809.08323v1 |
2018-09-24 | Simulation of muon-induced neutral particle background for a shallow depth Iron Calorimeter detector | The Iron Calorimeter (ICAL) detector at the India based Neutrino Observatory
(INO) is planned to be set up in an underground cavern with a rock overburden
of more than 1 km. This overburden reduces the cosmic muon flux by a factor of
10$^{6}$ with respect to that at sea level. In this paper, we examine the
possibility ... | 1809.08834v2 |
2018-09-27 | An investigation of the interrelationship between pressure and correlation in LaFeAsO under pressure | Here, we investigated the interrelationship between pressure and correlation
in the LaFeAsO compound by the density functional theory method combined with
the dynamical mean field theory (DFT+DMFT) method. The spectral function and
the occupation number (ON) of Fe-3d orbitals at different pressures were
extracted from ... | 1809.10661v1 |
2018-10-01 | Composition dependence of bulk superconductivity in YFe2Ge2 | In the layered iron-based superconductor YFe2Ge2, a high Sommerfeld ratio of
~100 mJ/molK^2 and a T^(3/2) temperature dependence of the electrical
resistivity at low temperature T indicate strong electronic correlations and
point towards an unconventional pairing state. We have investigated the role of
composition and ... | 1810.00947v1 |
2018-10-06 | Impact of Angular Deviation from Coincidence Site Lattice Grain Boundaries on Hydrogen Segregation and Diffusion in Alpha-iron | Coincidence Site Lattice (CSL) grain boundaries (GBs) are believed to be
low-energy, resistant to intergranular fracture, as well as to hydrogen
embrittlement. Nevertheless, the behavior of CSL-GBs are generally confused
with their angular deviations. In the current study, the effect of angular
deviation from the perfe... | 1810.02988v1 |
2018-10-10 | Superconductivity-induced nematicity | The role of nematic order for the mechanism of high-temperature
superconductivity is highly debated. In most iron-based superconductors (IBS)
the tetragonal symmetry is broken already in the normal state, resulting in
orthorhombic lattice distortions, static stripe magnetic order, or both.
Superconductivity then emerge... | 1810.04446v1 |
2018-10-15 | Evidence of nodal gap structure in the basal plane of the FeSe superconductor | Identifying the symmetry of the wave function describing the Cooper pairs is
pivotal in understanding the origin of high-temperature superconductivity in
iron-based superconductors. Despite nearly a decade of intense investigation,
the answer to this question remains elusive. Here we use the muon spin
rotation/relaxati... | 1810.06269v1 |
2018-11-13 | Nanoscale ordered Layered-Segregation of Cobalt and Iron in the Perovskite SmFe0.5Co0.5O3 | The possibility to segregate cobalt and iron in a single perovskite, at a
nanoscale in the form of layers has been investigated, using sol gel technic
synthesis. Quite remarkably, it is shown that such a nanoscale ordering, which
can only be detected by a combined HAADF-STEM and EELS study, has a significant
impact upo... | 1811.05221v1 |
2018-11-23 | Melting and phase change for laser-shocked iron | Using the LCLS facility at the SLAC National Accelerator Laboratory, we have
observed X-ray scattering from iron compressed with laser driven shocks to
Earth-core like pressures above 400GPa. The data shows shots where melting is
incomplete and we observe hexagonal close packed (hcp) crystal structure at
shock compress... | 1811.09467v1 |
2018-11-25 | Identification of two-dimensional $FeO_2$ termination of hematite $α-Fe_2O_3(0001)$ surface | Iron oxides are among the most abundant compounds on Earth and have
consequently been studied and used extensively in industrial processes. Despite
these efforts, concrete understanding of some of their surface phase structures
has remained elusive, in particular the oxidized ${\alpha}-Fe_2O_3(0001)$
hematite surface. ... | 1811.09996v1 |
2018-11-29 | Chemical evolution of the metal poor Globular Cluster NGC 6809 | We present the abundances analysis for a sample of 11 red giant branch stars
in the metal-poor globular cluster NGC 6809 based on high-resolution spectra.
Our main goals are to characterize its chemical composition and analyze this
cluster's behavior associated with the Multiple Population (MPs) phenomenon. In
our work... | 1811.12457v1 |
2018-11-30 | Magnetic and mechanical effects of Mn substitutions in AlFe2B2 | The mechanical and magnetic properties of the newly discovered MAB-phase
class of materials based upon AlFe2B2 were investigated. The samples were
synthesised from stoichiometric amounts of all constituent elements. X-ray
diffraction shows that the main phase is orthorhombic with an elongated b-axis,
similar to AlFe2B2... | 1811.12720v1 |
2018-12-24 | Magnetic measurements on micron-size samples under high pressure using designed NV centers | Pressure is a unique tool to tune the interplay between structural,
electronic and magnetic interactions. It leads to remarkable properties of
materials such as recent temperature records in superconductivity. Advanced
magnetic measurements under very high pressure in the Diamond Anvil Cell (DAC)
use synchrotron approa... | 1812.09894v1 |
2019-01-04 | Experimental and Numerical Investigation of the Fracture Behavior of Particle Reinforced Alkali Activated Slag Mortars | This paper presents fracture response of alkali-activated slag (AAS) mortars
with up to 30% (by volume) of slag being replaced by waste iron powder which
contains a significant fraction of elongated particles. The elongated iron
particles act as micro-reinforcement and improve the crack resistance of AAS
mortars by inc... | 1901.01025v1 |
2019-01-07 | Thermoelectric signature of the nematic phase in iron-based superconductor | Studies of the copper-based superconductors demonstrate how their phase
diagram becomes more complex as experimental probes improve, able to
distinguish among subtly different electronic phases. One of those phases,
nematicity, has become the matter of great interest also in the iron-based
superconductors, where it is ... | 1901.01788v2 |
2019-01-09 | Crystal structures and the sign reversal Hall resistivity in iron-based superconductors Lix(C3H10N2)0.32FeSe (0.15<x<0.4) | We report the crystal structure, superconductivity and normal state
properties of two iron-based materials, Li0.15(C3H10N2)0.32FeSe(P-4) and
Lix(C3H10N2)0.32FeSe(P4/nmm, 0.25<x<0.4) with superconducting transition
temperature from 40~46K. The determined crystal structures revealed a coupling
between Li concentration an... | 1901.02580v1 |
2019-01-11 | Carbon and oxygen in metal-poor halo stars | Carbon and oxygen are key tracers of the Galactic chemical evolution; in
particular, a reported upturn in [C/O] towards decreasing [O/H] in metal-poor
halo stars could be a signature of nucleosynthesis by massive Population III
stars. We reanalyse carbon, oxygen, and iron abundances in thirty-nine
metal-poor turn-off s... | 1901.03592v2 |
2019-01-11 | Discovery of stars surrounded by iron dust in the LMC | We consider a small sample of oxygen-rich, asymptotic giant branch stars in
the Large Magellanic Cloud, observed by the Spitzer Space Telescope, exhibiting
a peculiar spectral energy distribution, which can be hardly explained by the
common assumption that dust around AGB stars is primarily composed of silicate
grains.... | 1901.03621v1 |
2019-01-11 | Crystalline symmetry protected helical Majorana modes in the iron pnictides | We propose that propagating one-dimensional Majorana fermions will develop in
the vortex cores of certain iron-based superconductors, most notably
Li(Fe$_{1-x}$Co$_x$)As. A key ingredient of this proposal are the 3D Dirac
cones recently observed in ARPES experiments [P. Zhang et al., Nat. Phys.
$\textbf{15}$, 41 (2019)... | 1901.03692v3 |
2019-01-24 | Nuclear spallation in active galaxies | A number of works point to the presence of narrow emission features at
unusual energies in the X-ray spectra of active galactic nuclei (AGN) or to
potentially low iron abundances as possible evidence for the spallation of
iron. With the imminence of high-resolution calorimeter spectroscopy, the
potential to test spalla... | 1901.08383v1 |
2019-01-25 | Self-assembly of a binary mixture of iron oxide nanoparticles in Langmuir film: X-ray scattering study | In present study we exploited Langmuir technique to produce self-assembled
arrays composed of monodisperse iron oxide nanoparticles 10 nm and 20 nm in
diameter and of their binary mixture. A combination of in-situ X-ray
reflectometry and Grazing-incident small-Angle X-ray scattering was used to
obtain in-plane and out-... | 1901.08822v1 |
2019-01-28 | X-ray scattering characterization of iron oxide nanoparticles Langmuir film on water surface and on a solid substrate | In the present study we compare a structure of a Langmuir film assembled from
magnetic iron oxide nanoparticles on water surface and a structure of the same
film after its transfer to a solid substrate by the Langmuir-Schaefer method.
In contrast to most of related studies, where different techniques are used to
charac... | 1901.09636v1 |
2019-02-13 | Anisotropic thermal transport in magnetic intercalates Fe$_{x}$TiS$_2$ | We present a study of the of thermal transport in thin single crystals of
iron-intercalated titanium disulphide, Fe$_{x}$TiS$_2$ for $0\leq x \leq 0.20$.
We determine the distribution of intercalants using high-resolution
crystallographic and magnetic measurements, confirming the insertion of Fe
without long-range orde... | 1902.04975v1 |
2019-02-19 | Electronic structure of Ni-doped EuRbFe$_4$As$_4$: Unique crystal field splitting and multiband RKKY interactions | The relationship between magnetism and superconductivity has been one of the
most discussed topics in iron-based superconductors. Using the first-principles
calculations, we have studied the electronic structure of 1144-type iron-based
superconductor EuRbFe$_4$As$_4$. We find the crystal field splitting of
EuRbFe$_4$As... | 1902.06867v1 |
2019-03-01 | Topological Ultranodal pair states in iron-based superconductors | Bogoliubov Fermi surfaces are contours of zero-energy excitations that are
protected in the superconducting state. Here we show that multiband
superconductors with dominant spin singlet, intraband pairing of spin-1/2
electrons can undergo a transition to a state with Bogoliubov Fermi surfaces if
spin-orbit coupling, in... | 1903.00481v2 |
2019-03-04 | 57Fe enrichment in mice for \b{eta}-thalassaemia studies via Mossbauer spectroscopy of blood samples | In this work, wild-type and heterozygous \b{eta}-thalassaemic mice were
enriched with 57Fe through gastrointestinal absorption to characterize in more
details the iron complexes appeared in the measured Mossbauer spectra. The 57Fe
enrichment method was validated and Mossbauer spectra were obtained at 80K from
blood sam... | 1903.01245v2 |
2019-03-20 | Lifted electron pocket and reversed orbital occupancy imbalance in FeSe | The FeSe nematic phase has been the focus of recent research on iron based
superconductors (IBSs) due to its unique properties. A number of electronic
structure studies were performed to find the origin of the phase. However, such
attempts came out with conflicting results and caused additional controversies.
Here, we ... | 1903.08360v1 |
2019-03-20 | Discovery of polarizations from ground state absorption lines: tracer of sub-Gauss magnetic field on 89Her | We report the identification of the polarization of ground state absorption
lines from post-AGB 89~Hercules. Two ground state neutral iron lines are found
to have counterintuitive high-amplitude polarizations and an unchanged
polarization direction through the orbital period, as opposed to the pattern of
polarizations ... | 1903.08675v2 |
2019-04-12 | Quantitative characterization of short-range orthorhombic fluctuations in FeSe through pair distribution function analysis | Neutron and x-ray total scattering measurements have been performed on powder
samples of the iron chalcogenide superconductor FeSe. Using pair distribution
function (PDF) analysis of the total scattering data to investigate short-range
atomic correlations, we establish the existence of an instantaneous, local
orthorhom... | 1904.06440v2 |
2019-05-14 | Hidden robust presence of a hole Fermi surface in a heavily electron doped iron based superconductor LaFe$_2$As$_2$ | We investigate the electronic structure of a recently discovered, heavily
electron-doped iron based superconductor LaFe$_2$As$_2$. Although first
principles calculation shows apparent absence of hole Fermi surfaces around the
$\Gamma$ point, we reveal, by hypothetically removing the La $d$ orbital
contribution, that a ... | 1905.05488v2 |
2019-05-14 | Revealing the complex nature of bonding in binary high-pressure compound FeO$_2$ | Extreme pressures and temperatures are known to drastically affect the
chemistry of iron oxides resulting in numerous compounds forming homologous
series $n$FeO$\cdot m$Fe$_2$O$_3$ and the appearance of FeO$_2$. Here, based on
the results of \emph{in situ} single-crystal X-ray diffraction, M\"ossbauer
spectroscopy, X-r... | 1905.05497v2 |
2019-05-16 | Pressure-induced quantum critical point in a heavily hydrogen-doped iron-based superconductor LaFeAsO | An iron-based superconductor LaFeAsO$_{1-x}$H$_x$ (0 $\leq x \leq$ 0.6)
undergoes two antiferromagnetic (AF) phases upon H doping. We investigated the
second AF phase ($x$=0.6) using NMR techniques under pressure. At pressures up
to 2 GPa, the ground state is a spin-density-wave state with a large gap;
however, the gap... | 1905.06606v1 |
2019-05-16 | Thickness-dependent electron momentum relaxation times in thin iron films | Terahertz time-domain conductivity measurements in 2 to 100 nm thick iron
films resolve the femtosecond time delay between applied electric fields and
resulting currents. This response time decreases for thinner metal films. The
macroscopic response time depends on the mean and the variance of the
distribution of micro... | 1905.06739v1 |
2019-06-11 | Iron Embedded Magnetic Nanodiamonds for in vivo MRI Contrast Enhancement | Although nanodiamonds have long being considered as a potential tool for
biomedical research, the practical in vivo application of nanodiamonds remains
relatively unexplored. In this paper, we present the first application of in
vivo MRI contrast enhancement using only iron embedded magnetic nanodiamonds.
MR image enha... | 1906.04414v1 |
2019-06-12 | Many-body effects in porphyrin-like transition metal complexes embedded in graphene | We introduce a new computational method to study porphyrin-like transition
metal complexes, bridging density functional theory and exact many-body
techniques, such as the density matrix renormalization group (DMRG). We first
derive a multi-orbital Anderson impurity Hamiltonian starting from first
principles considerati... | 1906.05236v1 |
2019-06-07 | The influence of hydrogen core force shielding on dislocation junctions in iron | The influence of hydrogen on dislocation junctions was analysed by
incorporating a hydrogen dependent core force into nodal based discrete
dislocation dynamics. Hydrogen reduces the core energy of dislocations, which
reduces the magnitude of the dislocation core force. We refer to this as
hydrogen core force shielding,... | 1906.05344v2 |
2019-06-25 | First-principles study of the structural, electronic, magnetic and ferroelectric properties of a charge ordered Iron(II)- Iron(III) formate framework | Density functional theory calculations have been performed for the
structural, electronic, magnetic and ferroelectric properties of a
mixed-valence Fe(II)-Fe(III) formate framework [NH$_2$(CH$_3$)$_2$][Fe$^{\rm
III}$Fe$^{\rm II}$(HCOO)$_6$] (DMAFeFe). Recent experiments report a
spontaneous electric polarization and ou... | 1906.10512v1 |
2019-06-26 | Nanoscale Interlayer Defects in Iron Arsenides | Using a local real-space microscopy probe, we discover evidence of nanoscale
interlayer defects along the c-crystallographic direction in BaFe2As2 (122)
based iron-arsenide superconductors. We find ordered 122 atomic arrangements
within the ab-plane, and within regions of ~10 to 20 nm size perpendicular to
this plane. ... | 1906.11090v2 |
2019-06-27 | Contribution of type Ia supernovae to the chemical enrichment of the ultra-faint dwarf galaxy Bootes I | For three stars in the ultra-faint dwarf (UFD) galaxy Bootes I we have
determined the atmospheric parameters, performed a new reduction of
high-resolution spectra from the Subaru archive, and derived the abundances of
eight chemical elements without using the LTE assumption. As a result, among
the galaxies of its class... | 1906.11540v1 |
2019-07-01 | Bulk superconductivity and role of fluctuations in the iron-based superconductor FeSe at high pressures | The iron-based superconductor FeSe offers a unique possibility to study the
interplay of superconductivity with purely nematic as well magnetic-nematic
order by pressure (p) tuning. By measuring specific heat under p up to 2.36GPa,
we study the multiple phases in FeSe using a thermodynamic probe. We conclude
that super... | 1907.01015v2 |
2019-07-17 | Novel Receiver for Superparamagnetic Iron Oxide Nanoparticles in a Molecular Communication Setting | Superparamagnetic iron oxide nanoparticles (SPIONs) have recently been
introduced as information carriers in a testbed for molecular communication
(MC) in duct flow. Here, a new receiver for this testbed is presented, based on
the concept of a bridge circuit. The capability for a reliable transmission
using the testbed... | 1907.07805v1 |
2019-07-22 | Plaquette instability competing with bicollinear ground state in detwinned FeTe | We use inelastic neutron scattering to show that long-range spin waves
arising from the static bicollinear antiferromagnetic (AF) order in FeTe, which
have twofold rotational symmetry in a fully detwinned crystal, rapidly dissolve
above $E\approx 26$ meV into ridges of scattering with fourfold rotational
symmetry and a... | 1907.09420v1 |
2019-07-29 | Growth of nematic susceptibility in the field-induced normal state of an iron-based superconductor revealed by elastoresistivity measurements in a 65 T pulsed magnet | In the iron-based superconductors, both nematic and magnetic fluctuations are
expected to enhance superconductivity and may originate from a quantum critical
point hidden beneath the superconducting dome. The behavior of the
non-superconducting state can be an important piece of the puzzle, motivating
in this paper the... | 1907.12191v1 |
2019-08-02 | The superconductivity mechanism in Nd-1111 iron-based superconductor doped by calcium | We described the effect of nonmagnetic impurity on the superconductivity
behavior of the NdFeAsO0.8F0.2 iron-based superconductor. The resistivity
measurement showed that the superconductivity suppressed upon increasing the
low amounts of calcium impurity (x<0.05). Also, the Tc decreased with the
increase in the residu... | 1908.00675v1 |
2019-08-07 | Tunability of Room Temperature Ferromagnetism in Spintronic Semiconductors through Non-magnetic Atoms | The implementation and control of room temperature ferromagnetism (RTFM) by
adding magnetic atoms to a semiconductor's lattice has been one of the most
important problems in solid state state physics in the last decade. Herein we
report for the first time, to our knowledge, on the mechanism that allows RTFM
to be tuned... | 1908.02610v1 |
2019-08-07 | Momentum Dependence of the Nematic Order Parameter in Iron-Based Superconductors | The momentum dependence of the nematic order parameter is an important
ingredient in the microscopic description of iron-based high-temperature
superconductors. While recent reports on FeSe indicate that the nematic order
parameter changes sign between electron and hole bands, detailed knowledge is
still missing for ot... | 1908.02790v1 |
2019-08-12 | BaTh$_2$Fe$_4$As$_4$(N$_{0.7}$O$_{0.3}$)$_2$: An Iron-Based Superconductor Stabilized by Inter-Block-Layer Charge Transfer | Recently, An electron-doped 12442-type iron-based superconductor
BaTh$_2$Fe$_4$As$_4$(N$_{0.7}$O$_{0.3}$)$_2$ has been successfully synthesized
with high-temperature solid-state reactions on basis of a structural design.
The inter-block-layer charge transfer between the constituent units of
"BaFe$_2$As$_2$" and "ThFeAs... | 1908.03992v1 |
2019-08-28 | Synergy between Hund-driven correlations and boson-mediated Superconductivity | Multiorbital systems such as the iron-based superconductors provide a new
avenue to attack the longstanding problem of superconductivity in strongly
correlated systems. In this work we study the superconductivity driven by a
generic bosonic mechanism in a multiorbital model including the full dynamical
electronic corre... | 1908.10901v2 |
2019-08-28 | Impact of anharmonicity on sound wave velocities at extreme conditions | Theoretical calculations of sound-wave velocities of materials at extreme
conditions are of great importance to various fields, in particular geophysics.
For example, the seismic data on sound-wave propagation through the solid
iron-rich Earth's inner core have been the main source for elucidating its
properties and bu... | 1908.10927v1 |
2019-09-04 | Unconventional Multi-gap Superconductivity and Antiferromagnetic Spin Fluctuations in New Iron-arsenide LaFe2As2 in Heavily Electron-doped Regime | We report 75As-NMR/NQR results on new iron-arsenide compounds
(La0.5-xNa0.5+x)Fe2As2. The parent compound x=0 exhibits a stripe-type
antiferromagnetic (AFM) order below T_N=130 K. The measurement of nuclear spin
relaxation rate at hole-doped x=+0.3 and heavily electron-doped x=-0.5 revealed
that the normal-state proper... | 1909.01569v2 |
2019-08-28 | Artificial Neural Networks and Adaptive Neuro-fuzzy Models for Prediction of Remaining Useful Life | The U.S. water distribution system contains thousands of miles of pipes
constructed from different materials, and of various sizes, and age. These
pipes suffer from physical, environmental, structural and operational stresses,
causing deterioration which eventually leads to their failure. Pipe
deterioration results in ... | 1909.02115v1 |
2019-09-13 | A Neural Approach to Irony Generation | Ironies can not only express stronger emotions but also show a sense of
humor. With the development of social media, ironies are widely used in public.
Although many prior research studies have been conducted in irony detection,
few studies focus on irony generation. The main challenges for irony generation
are the lac... | 1909.06200v2 |
2019-09-18 | Observation of a C-type short range antiferromagnetic order in expanded FeS | We report neutron diffraction studies of FeS single crystals obtained from
Rb$_x$Fe$_{2-y}$S$_2$ single crystals via a hydrothermal method. While no
$\sqrt {5}\times \sqrt {5}$ iron vacancy order or block antiferromagnetic order
typical of Rb$_x$Fe$_{2-y}$S$_2$ is found in our samples, we observe $C$-type
short range a... | 1909.08325v1 |
2019-10-08 | The Triplet Resonating Valence Bond State and Superconductivity in Hund's Metals | A central idea in strongly correlated systems is that doping a Mott insulator
leads to a superconductor by transforming the resonating valence bonds (RVBs)
into spin-singlet Cooper pairs. Here, we argue that a spin-triplet RVB (tRVB)
state, driven by spatially, or orbitally anisotropic ferromagnetic interactions
can pr... | 1910.03168v2 |
2019-10-08 | AFeSe2 (A=Tl, K, Rb, or Cs): Iron-based superconducting analog of the cuprates | It has long been a challenging task to find compounds with similar crystal
and electronic structures as cuprate superconductors with low dimensionality
and strong antiferromagnetic fluctuations. The parent compounds of cuprate
superconductors are Mott insulators with strong in-plane antiferromagnetic
exchange interacti... | 1910.03545v2 |
2019-10-22 | An expression for the eddy field in a circular vacuum chamber for HEPS booster dipole | The analytical expression of the magnetic field distribution within the
aperture of a circular vacuum chamber due to the induced eddy is derived. Two
cases are discussed, one is the absence of iron, the other is that the vacuum
chamber is between the iron poles, that implies the use of the image current
methods. The cu... | 1910.09781v1 |
2019-10-22 | Ultrafast Quasiparticle Dynamics and Electron-Phonon Coupling in (Li0.84Fe0.16)OHFe0.98Se | Distinctive superconducting behaviors between bulk and monolayer FeSe make it
challenging to obtain a unified picture of all FeSe-based superconductors. We
investigate the ultrafast quasiparticle (QP) dynamics of an intercalated
superconductor (Li1-xFex)OHFe1-ySe, which is a bulk crystal but shares a
similar electronic... | 1910.09859v1 |
2019-11-13 | An investigation of the Brumadinho Dam Break with HEC RAS simulation | The Brumadinho dam disaster occurred on the 25 January, 2019 when Dam I, an
upstream tailings dam at the Corrego do Feijao iron ore mine, 9 kilometres (5.6
mi) east of Brumadinho, Minas Gerais, Brazil, suffered a catastrophic failure.
Over 248 people died and over 2.88 billion worth of property were lost or
damaged due... | 1911.05219v1 |
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