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2017-10-09
Appearance of a Domain Structure and its Electronic states in Iron Doped 1$T$-TaS$_2$ Observed using Scanning Tunneling Microscopy and Spectroscopy
In this paper, we report on scanning tunneling microscopy and spectroscopy (STM/STS) measurements on iron doped 1$T$-Ta$_{1-x}$Fe$_x$S$_2$. A novel domain structure composed of the domains with localized nature divided by the walls is observed in Ta$_{0.99}$Fe$_{0.01}$S$_2$, where the Mott transition is completely supp...
1710.02979v1
2017-11-07
Spin-Orbit Coupling and Magnetic Anisotropy in Iron-Based Superconductors
We determine theoretically the effect of spin-orbit coupling on the magnetic excitation spectrum of itinerant multi-orbital systems, with specific application to iron-based superconductors. Our microscopic model includes a realistic ten-band kinetic Hamiltonian, atomic spin-orbit coupling, and multi-orbital Hubbard int...
1711.02460v1
2017-11-15
Anisotropy of the Seebeck and Nernst coefficients in parent compounds of the iron-based superconductors
In-plane longitudinal and transverse thermoelectric phenomena in two parent compounds of iron-based superconductors are studied. Namely, the Seebeck (S) and Nernst (n) coefficients were measured in the temperature range 10 - 300 K for BaFe2As2 and CaFe2As2 single crystals that were detwinned in-situ. The thermoelectric...
1711.05831v2
2017-12-19
Emergent magnetic degeneracy in iron pnictides due to the interplay between spin-orbit coupling and quantum fluctuations
Recent experiments in iron pnictide superconductors reveal that, as the putative magnetic quantum critical point is approached, different types of magnetic order coexist over a narrow region of the phase diagram. Although these magnetic configurations share the same wave-vectors, they break distinct symmetries of the l...
1712.07188v4
2018-01-22
Excitation and charge transfer in low-energy hydrogen atom collisions with neutral iron
Data for inelastic processes due to hydrogen atom collisions with iron are needed for accurate modelling of the iron spectrum in late-type stars. Excitation and charge transfer in low-energy Fe+H collisions is studied theoretically using a previously presented method based on an asymptotic two-electron linear combinati...
1801.07050v1
2018-02-26
Iron-based trinuclear metal-organic nanostructures on a surface with local charge accumulation
Coordination chemistry relies on harnessing active metal sites within organic matrices. Polynuclear complexes - consisting of organic ligands binding to clusters of several metal atoms are of particular interest, owing to their electronic/magnetic properties and potential for functional reactivity pathways. However, th...
1802.09146v1
2018-03-02
Nonlinear uniaxial pressure dependence of $T_c$ in iron-based superconductors
We have systematically studied the effects of in-plane uniaxial pressure $p$ on the superconducting transition temperature $T_c$ in many iron-based superconductors. The change of $T_c$ with $p$ is composed of linear and nonlinear components. The latter can be described as a quadratic term plus a much smaller fourth-ord...
1803.00717v2
2018-04-11
Fe intercalation under graphene and hexagonal boron nitride in-plane heterostructure on Pt(111)
Metal nanostructures confined between sp2 hybridized 2D materials and solid supports are attracting attention for their potential application in new nanotechnologies. Model studies under well-defined conditions are valuable for understanding the fundamental aspects of the phenomena under 2D covers. In this work we inve...
1804.04240v1
2018-04-13
Experimental evidence of a body centered cubic iron at the Earth's core condition
The crystal structure of iron in the Earth's inner core remains debated. Most recent experiments suggest a hexagonal-close-packed (hcp) phase. In simulations, it has been generally agreed that the hcp-Fe is stable at inner core pressures and relatively low temperatures. At high temperatures, however, several studies su...
1804.05109v1
2018-04-19
Anisotropy of the DC conductivity due to orbital-selective spin fluctuations in the nematic phase of iron superconductors
We study the dc conductivity of iron-based superconductors within the orbital-selective spin fluctuation scenario. Within this approach, the anisotropy of spin fluctuations below the spin-nematic transition at T$_S$ is also responsible for the orbital ordering, induced by nematic self-energy corrections to the quasipar...
1804.07293v4
2018-05-09
Superconducting joint between iron-based superconductor tapes
Superconducting joints are essential for iron-based superconductor's applications in future. In this study, a process for fabricating superconducting joints between Sr1-xKxFe2As2 (Sr-122) tapes is developed for the first time. The Ag sheath was peeled off from one side of each sample. The exposed superconducting parts ...
1805.03399v1
2018-06-28
Fe3O4@astragalus polysaccharide core-shell nanoparticles for iron deficiency anemia therapy and magnetic resonance imaging in vivo
Fe3O4@astragalus polysaccharide core-shell nanoparticles (Fe3O4@APS NPs) were demonstrated to be an efficient therapeutic drug for treating iron deficiency anemia (IDA) in vivo. The Fe3O4@APS NPs have been synthesized using a two steps approach involving hydrothermal synthesis and subsequent esterification. Transmissio...
1806.10740v1
2018-07-25
Interplay between nematic fluctuation and superconductivity in the two-orbital Hubbard model: A quantum Monte Carlo study
To understand the interplay between nematic fluctuation and superconductivity in iron-based superconductors, we performed a systematic study of the realistic two-orbital Hubbard model by using the constrained-path quantum Monte Carlo method. Our numerical results showed that the on-site nematic interaction induces a st...
1807.09457v1
2018-08-17
Local Magnetic States of the Weakly Ferromagnetic Iron-Based Superconductor Sr$_2$VFeAsO$_{3-δ}$ Studied by X-ray Magnetic Circular Dichroism
We have performed x-ray magnetic circular dichroism (XMCD) measurements on the iron-based superconductor Sr$_2$VFeAsO$_{3-\delta}$ to study the origin of weak ferromagnetism (WFM) reported for this compound. While Fe 3$d$ electrons show a magnetic response similar to the other iron pnictides, signals from V 3$d$ electr...
1808.05715v3
2018-08-30
Selective Aggregation Experiments on Planetesimal Formation and Mercury-Like Planets
Much of a planet's composition could be determined right at the onset of formation. Laboratory experiments can constrain these early steps. This includes static tensile strength measurements or collisions carried out under Earth's gravity and on various microgravity platforms. Among the variety of extrasolar planets wh...
1808.10246v1
2018-09-10
Hedgehog Spin-vortex Crystal Antiferromagnetic Quantum Criticality in CaK(Fe1-xNix)4As4 Revealed by NMR
Two ordering states, antiferromagnetism and nematicity, have been observed in most iron-based superconductors (SCs). In contrast to those SCs, the newly discovered SC CaK(Fe$_{1-x}$Ni$_x$)$_4$As$_4$ exhibits an antiferromagnetic (AFM) state, called hedgehog spin-vortex crystal structure, without nematic order, providin...
1809.03354v1
2018-11-06
First study on iron complexes in blood and organ samples from thalassaemic and normal laboratory mice using Moessbauer spectroscopy
In this paper, blood and tissues samples from one normal and one thalassaemic lab-mice were studied using 57Fe Mossbauer spectroscopy at 78K for the first time. In contrast to human patients, these laboratory mice did not receive any medical treatment, thus the iron components present in the samples are not altered. Th...
1811.02594v1
2018-12-16
Strong electron-boson coupling in the iron-based superconductor BaFe1.9Pt0.1As2 revealed by infrared spectroscopy
Understanding the formation of Cooper pairs in iron-based superconductors is one of the most important topics in condensed matter physics. In conventional superconductors, the electron-phonon interaction leads to the formation of Cooper pairs. In conventional strong-coupling superconductors like lead (Pb), the features...
1812.06546v1
2018-12-26
Helical Hinge Majoranas in Iron-Based Superconductors
Motivated by recent experiments on FeTe$_{1-x}$Se$_{x}$, we construct an explicit minimal model of an iron-based superconductor with band inversion at the $Z$ point and non-topological bulk $s_{\pm}$ pairing. While there has been considerable interest in Majorana zero modes localized at vortices in such systems, we fin...
1812.10493v2
2019-01-01
A strongly inhomogeneous superfluid in an iron-based superconductor
Among the mysteries surrounding unconventional, strongly correlated superconductors is the possibility of spatial variations in their superfluid density. We use atomic-resolution Josephson scanning tunneling microscopy to reveal a strongly inhomogeneous superfluid in the iron-based superconductor FeTe0.55Se0.45. By sim...
1901.00149v1
2019-01-29
Interaction between Molecular Clouds and MeV-TeV Cosmic-ray Protons Escaped from Supernova Remnants
Recent discovery of the X-ray neutral iron line (Fe I K\alpha at 6.40 keV) around several supernova remnants (SNRs) show that MeV cosmic-ray (CR) protons are distributed around the SNRs and are interacting with neutral gas there. We propose that these MeV CRs are the ones that have been accelerated at the SNRs together...
1901.10477v3
2019-03-01
Broken mirror symmetry, incommensurate spin correlations, and $B_{2g}$ nematic order in iron pnictides
Motivated by growing indications for a distinct form of nematic correlations in the extremely hole doped iron pnictide compounds $A$Fe$_2$As$_2$ ($A$=K,Rb,Cs), we consider spin-driven nematic order in the general case of incommensurate magnetic fluctuations. We classify the nematic order parameters by broken mirror sym...
1903.00375v2
2019-03-12
Epsilon-iron as a spin-smectic state
Using x-ray emission spectroscopy, we find appreciable local magnetic moments until 30-40 GPa in the high-pressure phase of iron, however no magnetic order is detected with neutron powder diffraction down to 1.8 K contrary to previous predictions. Our first-principles calculations reveal a "spin-smectic" state lower in...
1903.04792v2
2019-03-15
Plasma environment effects on K lines of astrophysical interest. II. Ionization potentials, K thresholds, radiative rates and Auger widths in Ne- through He-like iron ions (Fe xvii - Fe xxv)
Aims. In the context of accretion disks around black holes, we estimate plasma-environment effects on the atomic parameters associated with the decay of K-vacancy states in highly charged iron ions, namely Fe xvii - Fe xxv. Methods. Within the relativistic multiconfiguration Dirac-Fock (MCDF) framework, the electron-nu...
1903.06458v1
2019-04-11
Strain tuning and anisotropic spin correlations in iron-based systems
Nematic order in the iron-based superconductors is closely tied to a lattice distortion and a structural transition from tetragonal to orthorhombic symmetry. External stress of the appropriate symmetry acts as a conjugate field of the nematic order parameter and can be utilized to detwin nematic domains but also smears...
1904.05583v2
2019-04-27
Neutron star radius measurement from the ultraviolet and soft X-ray thermal emission of PSR J0437-4715
We analyzed the thermal emission from the entire surface of the millisecond pulsar PSR J0437-4715 observed in the ultraviolet and soft X-ray bands. For this, we calculated non-magnetized, partially ionized atmosphere models of hydrogen, helium, and iron compositions and included plasma frequency effects that may affect...
1904.12114v2
2019-05-01
p-Wave Superconductivity in Iron-based Superconductors
The possibility of p-wave pairing in superconductors has been proposed more than five decades ago, but has not yet been convincingly demonstrated. One difficulty is that some p-wave states are thermodynamically indistinguishable from s-wave, while others are very similar to d-wave states. Here we studied the self-field...
1905.00183v3
2019-06-21
Topological Crystalline Superconductivity in Dirac Semimetal Phase of Iron-based Superconductors
In iron-based superconductors, band inversion of $d$- and $p$-orbitals yields Dirac semimetallic states. We theoretically investigate their topological properties in normal and superconducting phases, based on the tight-binding model involving full symmetry of the materials. We demonstrate that a Cooper pair between el...
1906.09286v1
2019-08-30
Magnetic states of iron-based two-leg ladder tellurides
The recent discovery of superconductivity at high pressure in the two-leg ladder compounds BaFe$_2X_3$ ($X$=S, Se) started the novel field of quasi-one-dimensional iron-based superconductors. In this publication, we use Density Functional Theory (DFT) to predict that the previously barely explored ladder compound RbFe$...
1908.11765v2
2019-09-10
Anisotropic magnetic excitations of a frustrated bilinear-biquadratic spin model -- Implications for spin waves of detwinned iron pnictides
Elucidating the nature of spin excitations is important to understanding the mechanism of superconductivity in the iron pnictides. Motivated by recent inelastic neutron scattering measurements in the nearly 100% detwinned BaFe$_{2}$As$_{2}$, we study the spin dynamics of an $S=1$ frustrated bilinear-biquadratic Heisenb...
1909.04555v2
2019-09-21
Dynamical stability of radiation-induced C15 clusters in iron
Density functional theory predicts clusters in the form of the C15 Laves phase to be the most stable cluster of self-interstitials in iron at small sizes. The C15 clusters can form as a result of irradiation, but their prevalence and survival in harsh irradiation conditions have not been thoroughly studied. Using a new...
1909.09818v1
2019-10-31
Quantum critical nematic fluctuations and spin excitation anisotropy in iron pnictides
Quantum criticality in iron pnictides involves both the nematic and antiferromagnetic degrees of freedom, but the relationship between the two types of fluctuations has yet to be clarified. Here we study this problem in the presence of a small external uniaxial potential, which breaks the $C_4$-symmetry in the B$_{1g}$...
1910.14597v4
2019-12-11
Hypothetical hyperbolic encounters between Venus and proto-Mercury that partially \ stripped away proto-Mercury's mantle
Mercury has an unusually large metal core comprising ~70% of its mass comparing to all other terrestrial planets in the solar system. Giant impacts can remove a significant fraction of the silicate mantle of a chondritic proto-Mercury and form the iron rich present-day Mercury. However, such high-temperature giant impa...
1912.05219v1
2019-12-12
X-ray reverberation lags from the 1.5 Seyfert galaxy NGC 5273
We present the results of X-ray spectral-timing analysis of a 90ks XMM-Newton observation of the nearby, broad line, early-type AGN NGC5273. The X-ray spectrum revealed the clear presence of a reflection component at high energies, with a clear signature of a narrow iron line at 6.4 keV, consistent with distant reflect...
1912.06196v1
2020-02-18
Low work function in the 122-family of iron-based superconductors
We determine the work functions of the iron arsenic compounds $A$Fe$_2$As$_2$ ($A=\mathrm{Ca, Ba, Cs}$) using photoemission spectroscopy to be 2.7 eV for CaFe$_2$As$_2$, 1.8 eV for BaFe$_2$As$_2$, and 1.3 eV for CsFe$_2$As$_2$. The work functions of these 122 iron-based superconductors track those of the elementary met...
2002.07924v1
2020-02-21
Iron Line Tomography of General Relativistic Hydrodynamic Accretion around Kerr Black Holes
We consider a temporal response of relativistically broadened line spectrum of iron from black hole accretion irradiated by an X-ray echo under strong gravity. The physical condition of accreting gas is numerically calculated in the context of general relativistic hydrodynamics under steady-state, axisymmetry in Kerr g...
2002.09550v1
2020-02-22
Molecular static simulation of edge dislocation core in bcc iron
We simulate the dislocation core structure in bcc iron using the modified Molecular Static method. A feature of this method is the application of an iterative procedure in which the atomic structure in the vicinity of the defect and the constants that determine the displacements of atoms immersed in the elastic continu...
2002.09601v2
2020-02-25
A Type Ia supernova at the heart of superluminous transient SN 2006gy
Superluminous supernovae radiate up to 100 times more energy than normal supernovae. The origin of this energy and the nature of their stellar progenitors are poorly understood. We identify neutral iron lines in the spectrum of one such transient, SN 2006gy, and show that they require a large mass of iron (>~0.3 Msun) ...
2002.10768v1
2020-05-07
In the Pursuit of Majorana Modes in Iron-based High-$T_c$ Superconductors
Majorana zero mode is an exotic quasi-particle excitation with non-Abelian statistics in topological superconductor systems, and can serve as the cornerstone for topological quantum computation, a new type of fault-tolerant quantum computation architecture. This review paper highlights recent progress in realizing Majo...
2005.03603v1
2020-05-11
Simplified ResNet approach for data driven prediction of microstructure-fatigue relationship
The heterogeneous microstructure in metallic components results in locally varying fatigue strength. Metal fatigue strongly depends on size and shape of non-metallic inclusions and pores, commonly referred to as "defects". Nodular cast iron (NCI) contains graphite inclusions (nodules) whose shape and frequency influenc...
2005.06615v1
2020-06-05
Observation of Two-dimensional Superconductivity in an Ultrathin Iron-Arsenic Superconductor
Two-dimensional (2D) superconductors supply important platforms for exploring new quantum physics and high-$T_c$ superconductivity. The intrinsic superconducting properties in the 2D iron-arsenic superconductors are still unknown owing to the difficulties in the preparation of ultrathin samples. Here we report the fabr...
2006.03338v1
2020-06-24
Composition and Size Dependent Sorting in Preplanetary Growth: Seeding the Formation of Mercury-like Planets
In an earlier work, we found that large metallic iron fractions in dust aggregates and strong magnetic fields boost preplanetary growth. This sets an initial bias for the formation of Mercury-like planets in the inner part of protoplanetary disks. We extended these experiments here by adding pure quartz aggregates to t...
2006.13692v1
2020-07-14
In-plane p-wave coherence length in iron-based superconductors
High-temperature superconductivity in iron-based layered compounds discovered by Hosono group (Kamihara et al 2006 J. Am. Chem. Soc. 128 10012) is fascinating physical phenomenon which still has many unanswered questions. One of these questions is the superconducting gap symmetry in iron-based superconductors (IBS), fo...
2007.07110v1
2020-08-20
Canted Antiferromagnetism in the Quasi-1D Iron Chalcogenide BaFe$_{2}$Se$_{4}$
We report the synthesis and physical properties studies of quais-1D iron chalcogenide $\rm BaFe_2Se_4$ which shares the $\rm FeSe_4$ tetrahedra building motif commonly seen in the iron chalcogenide superconductors. A high-quality polycrystalline sample was achieved by solid-state reaction method and characterized by X-...
2008.08809v1
2020-09-04
Strong enhancement of magnetic order from bulk to stretched monolayer FeSe as Hund's metals
Despite of the importance of magnetism in possible relation to other key properties in iron-based superconductors, its understanding is still far from complete especially for FeSe systems. On one hand, the origin of the absence of magnetic orders in bulk FeSe is yet to be clarified. On the other hand, it is still not c...
2009.02024v1
2020-09-24
Probing redox potential for Iron sulfur clusters in photosystem I
Photosystem I is a light-driven electron transfer device. Available X-ray crystal structure from Thermosynechococcus elongatus, showed that electron transfer pathways consist of two nearly symmetric branches of cofactors converging at the first iron sulfur cluster FX, which is followed by two terminal iron sulfur clust...
2009.11681v1
2020-10-11
Electrical properties of thermal oxide scales on pure iron in liquid lead-bismuth eutectic
The impedance behavior of pre-oxidized iron in liquid lead-bismuth eutectic (LBE) at 200 oC is studied using electrochemical impedance spectroscopy. The structures and resistance of oxide grown on iron oxidized in air at different temperatures and durations are compared. The results show that the resistance of the oxid...
2010.05372v1
2020-10-15
Anomalous thermal properties and spin crossover of ferromagnesite (Mg,Fe)CO3
Ferromagnesite (Mg,Fe)CO3, also referred to as magnesiosiderite at high iron concentration, is a solid solution of magnesite (MgCO3) and siderite (FeCO3). Ferromagnesite is believed to enter the Earth's lower mantle via subduction and is considered a major carbon carrier in the Earth's lower mantle, playing a key role ...
2010.07720v2
2020-11-11
Electron doping of the iron-arsenide superconductor CeFeAsO controlled by hydrostatic pressure
In the iron-pnictide material CeFeAsO not only the Fe moments, but also the local 4f moments of the Ce order antiferromagnetically at low temperatures. We elucidate on the peculiar role of the Ce on the emergence of superconductivity. While application of pressure suppresses the iron SDW ordering temperature monotonous...
2011.05665v1
2020-11-17
Dichotomy Between Orbital and Magnetic Nematic Instabilities in BaFe2S3
Nematic orders emerge nearly universally in iron-based superconductors, but elucidating their origins is challenging because of intimate couplings between orbital and magnetic fluctuations. The iron-based ladder material BaFe2S3, which superconducts under pressure, exhibits antiferromagnetic order below TN ~ 117K and a...
2011.08600v1
2020-11-25
Expansion and Age of the Supernova Remnant G350.1-0.3: High-Velocity Iron Ejecta from a Core-Collapse Event
We report Chandra observations of the highly asymmetric core-collapse supernova remnant G350.1-0.3. We document expansion over 9 years away from the roughly stationary central compact object, with sky-plane velocities up to $5000 d_{4.5}$ km s$^{-1}$ ($d_{4.5}$ is the distance in units of 4.5 kpc), redshifts ranging fr...
2011.12977v2
2020-12-18
Efficient Analytical Approach for High-Pressure Melting Properties of Iron
Iron represents the principal constituent of the Earth's core, but its high-pressure melting diagram remains ambiguous. Here we present a simple analytical approach to predict the melting properties of iron under deep-Earth conditions. In our model, anharmonic free energies of the solid phase are directly determined by...
2012.10023v1
2021-02-19
Thermodynamic electric quadrupole moments of nematic phases from first-principles calculation
The electronic nematic phase emerging with spontaneous rotation symmetry breaking is a central issue of modern condensed matter physics. In particular, various nematic phases in iron-based superconductors and high-$T_{\rm c}$ cuprate superconductors are extensively studied recently. Electric quadrupole moments (EQMs) a...
2102.09783v1
2021-03-16
Accretion geometry of the black hole binary MAXI J1820+070 probed by frequency-resolved spectroscopy
The geometry of the inner accretion flow in the hard and hard-intermediate states of X-ray binaries remains controversial. Using NICER observations of the black hole X-ray binary MAXI J1820+070 during the rising phase of its 2018 outburst, we study the evolution of the timing properties, in particular the characteristi...
2103.08795v1
2021-03-16
Emerging symmetric strain response and weakening nematic fluctuations in strongly hole-doped iron-based superconductors
Electronic nematicity is often found in unconventional superconductors, suggesting its relevance for electronic pairing. In the strongly hole-doped iron-based superconductors, the symmetry channel and strength of the nematic fluctuations, as well as the possible presence of long-range nematic order, remain controversia...
2103.08972v1
2021-05-25
Dynamics of particles with cubic magnetic anisotropy in a viscous liquid
The specific absorption rate (SAR) of a dilute assembly of spherical iron nanoparticles with cubic anisotropy distributed in a viscous liquid is calculated using the solution of stochastic Landau - Lifshitz equation for unit magnetization vector and stochastic equations for multiple particle directors that specify the ...
2105.11916v1
2021-06-06
Testing the Kerr black hole hypothesis with GRS 1716-249 by combining the continuum-fitting and the iron-line methods
The continuum-fitting and the iron-line methods are currently the two leading techniques for measuring the spins of accreting black holes. In the past few years, these two methods have been developed for testing fundamental physics. In the present work, we employ state-of-the-art models to test black holes through the ...
2106.03086v2
2021-06-21
Testing the Kerr black hole hypothesis with the continuum-fitting and the iron line methods: the case of GRS 1915+105
The continuum-fitting and the iron line methods are currently the two leading techniques for probing the strong gravity region around accreting black holes. In the present work, we test the Kerr black hole hypothesis with the stellar-mass black hole in GRS 1915+105 by analyzing five disk-dominated RXTE spectra and one ...
2106.10982v2
2021-06-24
Artificial neural network molecular mechanics of iron grain boundaries
This study reports grain boundary (GB) energy calculations for 46 symmetric-tilt GBs in alpha-iron using molecular mechanics based on an artificial neural network (ANN) potential and compares the results with calculations based on the density functional theory (DFT), the embedded atom method (EAM), and the modified EAM...
2106.12745v1
2021-08-12
Polarized neutron scattering studies of magnetic excitations in iron-selenide superconductor (Li$_{0.8}$Fe$_{0.2}$)ODFeSe ($T_c$ = 41 K)
We report polarized neutron scattering measurements of the low energy spin fluctuations of the iron-selenide superconductor Li$_{0.8}$Fe$_{0.2}$ODFeSe below and above its superconducting transition temperature $T_c=41$ K. Our experiments confirmed that the resonance mode near 21 meV is magnetic. Moreover, the spin exci...
2108.05832v1
2021-08-25
Cooling Delays from Iron Sedimentation and Iron Inner Cores in White Dwarfs
Do white dwarfs have inner cores made of iron? Neutron rich nuclei like $^{56}$Fe experience a net gravitational force and sediment toward the core. Using new phase diagrams and molecular dynamics simulations, we show that $^{56}$Fe should separate into mesoscopic Fe-rich crystallites due to its large charge relative t...
2108.11389v1
2021-09-10
Interference Effect of Beam Splitter Current in Iron-Pnictide Superconductors
We consider a Cooper pair beam splitter for Iron-Pnictide superconductor and calculate the entangled electron-hole current. We investigate the interplay of various physical parameters such as doping at electron and hole pockets as well as non-zero nesting between the electron and hole pocket. We find that in the absenc...
2109.04796v2
2021-09-19
Data analysis of $ab$ $initio$ effective Hamiltonians in iron-based superconductors $\unicode{x2014}$ Construction of predictors for superconducting critical temperature
High-temperature superconductivity occurs in strongly correlated materials such as copper oxides and iron-based superconductors. Numerous experimental and theoretical works have been done to identify the key parameters that induce high-temperature superconductivity. However, the key parameters governing the high-temper...
2109.09121v2
2021-10-01
Iron-rich Fe-O compounds with closest-packed layers at core pressures
Oxygen solubility in solid iron is extremely low, even at high pressures and temperatures. Thus far, no Fe-O compounds between Fe and FeO endmembers have been reported experimentally. We observed chemical reactions of Fe with FeO or Fe$_2$O$_3$ $in\ situ$ x-ray diffraction experiments at 220-260 GPa and 3,000-3,500 K. ...
2110.00524v1
2021-11-22
Oxygen-driven enhancement of electron correlation in hexagonal iron at Earth's inner core conditions
Earth's inner core consists of mainly iron with a bit of light elements. Understanding of its structure and related physical properties has been elusive for both experiment and theory due to its required extremely high pressure and temperature conditions. Here, using density functional theory plus dynamical mean field ...
2111.11033v1
2021-12-01
Comparison of hydrogen diffusivities measured by electrochemical permeation and temperature-programmed desorption in cold-rolled pure iron
The diffusivity of hydrogen in cold-rolled pure iron is investigated using permeation and desorption methods. Electrochemical charging, electro-permeation and thermal desorption spectroscopy (TDS) experiments are conducted. Firstly, the relation between the charging current and the hydrogen concentration is established...
2112.00589v1
2022-01-27
FeSe and the missing electron pocket problem
The nature and origin of electronic nematicity remains a significant challenge in our understanding of the iron-based superconductors. This is particularly evident in the iron chalcogenide, FeSe, where it is currently unclear how the experimentally determined Fermi surface near the M point evolves from having two elect...
2201.11702v1
2022-02-01
Ubiquitous enhancement of nematic fluctuations across the phase diagram of iron based superconductors probed by the Nernst effect
The role of nematic fluctuations for unconventional superconductivity has been subject of intense discussions for many years. In iron-based superconductors, the most established probe for electronic-nematic fluctuations, i.e. the elastoresistivity seems to imply that superconductivity is reinforced by electronic-nemati...
2202.00485v1
2022-02-14
Hydrothermal synthesis, structure, and antibacterial studies of a nanosized iron zeolite
The present research explores the effects of Percentage Fe incorporation on the structure and antibacterial activity of Fe ZSM 5. Silica extracted from local rice husk straw (white particles) by applying NaOH and HCl solutions for consecutive chemical treatment was used for hydrothermal synthesis of FeZSM 5 with consta...
2202.06900v1
2022-03-01
Ultrafast Melting of Superconductivity in an Iron-Based Superconductor
Intense debate has recently arisen regarding the photoinduced changes to the iron-chalcogenide superconductors, including the enhancement of superconductivity and a metastable state. Here, by employing high energy resolution, we directly observe the melting of superconductivity on ultrafast timescales. We demonstrate a...
2203.00678v2
2022-03-26
Ferromagnetic Impurity Induced Majorana Zero Mode in Iron-Based Superconductor
Recent experiments reported the puzzling zero energy modes associated with ferromagnetic impurities in some iron-based superconductors with topological band structures. Here, we show that the sufficiently strong exchange coupling between a ferromagnetic impurity and substrate can trigger a quantum phase transition, bey...
2203.14017v3
2022-04-14
Orbital memory from individual Fe atoms on black phosphorus
Bistable valency in individual atoms presents a new approach toward single-atom memory, as well as a building block to create tunable and stochastic multi-well energy landscapes. Yet, this concept of orbital memory has thus far only been observed for cobalt atoms on the surface of black phosphorus, which are switched u...
2204.06915v1
2022-04-19
Recycling End-of-life Polycarbonate in Steelmaking; $\textit{Ab Initio}$ Study of Carbon Dissolution in Molten Iron
The scarcity of fossil fuels as carbon resources has motivated the steelmaking industry to search for new carbon sources such as end-of-life polymeric products. Using $\textit{ab initio}$ molecular dynamics simulation, we demonstrate that 41% of polycarbonate's carbon content is readily dissolved in molten iron's inter...
2204.08706v1
2022-04-20
Control of magnetic susceptibility of probiotic strain Lactobacillus Rhamnosus GG
The paper investigates the increase in the natural magnetically controlled properties of probiotic microorganisms Lactobacillus rhamnosus GG (LGG) and their ability to form magnetic sensitive inclusions (MsI). The magnetic susceptibility of LGG was increased by modifying the nutrient medium composition and by cultivati...
2204.09338v1
2022-04-27
On the possibility of incorporation of the iron impurity into $A$ sites in SrTiO$_3$
The local environment and oxidation state of the Fe impurity in strontium titanate are studied using XAFS spectroscopy. The influence of annealing temperature and deviation from stoichiometry on the possibility of incorporation of the impurity into the $A$ and $B$ sites of the perovskite structure is studied. The resul...
2204.12775v2
2022-05-04
Ab initio melting temperatures of bcc and hcp iron under the Earth's inner core condition
There has been a long debate on the stable phase of iron under the Earth's inner core conditions. Because of the solid-liquid coexistence at the inner core boundary, the thermodynamic stability of solid phases directly relates to their melting temperatures, which remains considerable uncertainty. In the present study, ...
2205.02290v2
2022-08-03
Magnetic biophysical characterization of biomimetic polyeth-ylenimine-coated nanoparticles on in vitro silico model
Understanding the biophysical and magnetic interactions of nanoparticles (NPs) with cell mem-branes is critical for developing effective nanocarrier systems for drug delivery applications and targeted nanophysics applications. Recent discoveries in nanomedicine can be used to test an in vitro system that reproduce a si...
2208.02838v1
2022-09-29
Exploring Supernova Gravitational Waves with Machine Learning
Core-collapse supernovae (CCSNe) emit powerful gravitational waves (GWs). Since GWs emitted by a source contain information about the source, observing GWs from CCSNe may allow us to learn more about CCSNs. We study if it is possible to infer the iron core mass from the bounce and early ring-down GW signal. We generate...
2209.14542v2
2022-11-03
Magnetism in Two-Dimensional Ilmenenes: Intrinsic Order and Strong Anisotropy
Iron ilmenene is a new two-dimensional material that has recently been exfoliated from the naturally-occurring iron titanate found in ilmenite ore, a material that is abundant on earth surface. In this work, we theoretically investigate the structural, electronic and magnetic properties of 2D transition-metal-based ilm...
2211.01732v1
2023-02-03
Effect of iron thicknesses on spin transport in a Fe/Au bilayer system
This paper is concerned with a theoretical analysis of the behavior of optically excited spin currents in bilayer and multilayer systems of ferromagnetic and normal metals. As the propagation, control and manipulation of the spin currents created in ferromagnets by femtosecond optical pulses is of particular interest, ...
2302.01472v1
2023-06-13
Origin of superionic state in Earth's inner core
Earth's inner core (IC) serves as a reservoir for volatile elements, which significantly affects its behavior and properties. Recent studies suggest that superionicity can be observed in ice and iron hydrides under high-pressure and temperature conditions, providing an alternative understanding of the planet's interior...
2306.07534v1
2023-06-14
Slope of the upper critical field at $T_{c}$ in two-band superconductors with non-magnetic disorder: $s_{++}$ superconductivity in $\textrm{Ba}_{1-x}\textrm{K}_{x}\textrm{Fe}_{2}\textrm{As}_{2}$
A recent theory of the disorder-dependent slope of the upper critical field, $H_{c2}$, at the superconducting transition temperature, $T_{c}$, is extended to multiband superconductors aiming at iron-based superconductors, considering two constant gaps of different magnitude and, potentially, different signs. The result...
2306.08703v2
2023-06-22
Data-Driven Update of B(H) Curves of Iron Yokes in Normal Conducting Accelerator Magnets
Constitutive equations are used in electromagnetic field simulations to model a material response to applied fields or forces. The $B(H)$ characteristic of iron laminations depends on thermal and mechanical stresses that may have occurred during the manufacturing process. Data-driven modelling and updating of the $B(H)...
2306.12872v1
2023-09-30
High gas pressure and high-temperature synthesis (HP-HTS) technique and its impact on iron-based superconductors
The high-pressure growth technique generally plays an important role in the improvement of the sample quality and the enhancement of various physical and magnetic properties of materials. The high gas pressure technique provides a large sample space (10-15 cm) to grow various kinds of materials. In this paper, we intro...
2310.00282v1
2023-10-09
Detection of Iron in Nanoclustered Cytochrome C Proteins Using Nitrogen-Vacancy Magnetic Relaxometry
Nitrogen-vacancy (NV) magnetometry offers an alternative tool to detect iron levels in neurons and cells with a favorable combination of magnetic sensitivity and spatial resolution. Here we employ NV-T1 relaxometry to detect Fe in cytochrome C (Cyt-C) nanoclusters. Cyt-C is a water-soluble protein that contains a singl...
2310.08605v2
2023-11-10
Machine Learning-Driven Structure Prediction for Iron Hydrides
We created a computational workflow to analyze the potential energy surface (PES) of materials using machine-learned interatomic potentials in conjunction with the minima hopping algorithm. We demonstrate this method by producing a versatile machine-learned interatomic potential for iron hydride via a neural network us...
2311.06010v1
2023-11-15
Probing Iron in Earth's Core With Molecular-Spin Dynamics
Dynamic compression of iron to Earth-core conditions is one of the few ways to gather important elastic and transport properties needed to uncover key mechanisms surrounding the geodynamo effect. Herein a new machine-learned ab-initio derived molecular-spin dynamics (MSD) methodology with explicit treatment for longitu...
2311.08737v1
2023-11-21
Speciation controls the kinetics of iron hydroxide precipitation and transformation
The formation of energetically favourable and metastable mineral phases within the Fe-H2O system controls the long-term mobility of iron complexes as well as other aqueous phase constituents in natural aquifers, soils and other environmentally and industrially relevant systems. The fundamental mechanism controlling the...
2311.12464v1
2024-01-04
Exploring the Unconventional Electron Distribution Patterns in Iron-based Superconductors
For more than a decade, the unusual distribution of electrons observed in ARPES (angle-resolved photoemission spectroscopy) data within the energy range of ~30meV to ~300meV below the Fermi level, known as the ARPES range, has remained a puzzle in the field of iron-based superconductivity. However, in this study, we ha...
2401.02140v1
2024-01-16
Unusually weak irradiation effects in anisotropic iron-based superconductor RbCa2Fe4As4F2
We report on the effects of 3.5 MeV proton irradiation in RbCa$_2$Fe$_4$As$_4$F$_2$, an iron-based superconductor with unusual properties in between those of the pnictides and of the cuprate high-temperature superconductors. We studied how structural disorder introduced by ion bombardment affects the critical temperatu...
2401.08279v1
2024-01-18
X-ray Iron absorption line in Swift J1858.6-0814
We present the spectral analysis of bright steady states in an outburst of the transient neutron star low-mass X-ray binary (NS-LMXB) Swift J1858.6-0814 observed with NICER. We detected an ionized iron K absorption line (H-like Fe) at 6.97keV in the spectrum. We estimated the photoionization parameter using the ratio o...
2401.09664v1
2024-01-31
Tailoring magnetic and hyperthermia properties of biphase iron oxide nanocubes through post-annealing
Tailoring the magnetic properties of iron oxide nanosystems is essential to expand their biomedical applications. In this study, the 34 nm iron oxide nanocubes with two phases consisting of Fe3O4 and alpha-Fe2O3 were annealed for 2 hours in the presence of O2, N2, He, and Ar to tune the respective phase volume fraction...
2401.18009v1
2024-03-19
Growth of metal catalyst nanoparticles in hydrocarbon-rich atmosphere of arc discharge for synthesis of carbon nanotubes
A direct current (DC) arc discharge is a widely used method for industrial-scale production of single-walled carbon nanotubes (SWCNT). A high-selectivity synthesis of SWCNT requires ultra-fine, typically a few nanometers in diameter, catalyst particles, which is challenging to achieve in harsh arc environments involvin...
2403.12700v1
2004-08-18
Heavy elements and chemical enrichment in globular clusters
High resolution (R > 40 000) and high S/N spectra have been acquired with UVES on the VLT-Kueyen (Paranal Observatory, ESO Chile) for several main sequence turnoff stars (V ~ 17 mag) and subgiants at the base of the Red Giant Branch (V ~ 16 mag) in three globular clusters (NGC 6397, NGC 6752 and 47 Tuc/NGC 104) at diff...
0408330v1
1993-11-15
Spin Gaps and Bilayer Coupling in YBa$_2$Cu$_3$O$_{7-δ}$ and YBa$_2$Cu$_4$O$_8$
We investigate the relevance to the physics of underdoped YBa$_2$Cu$_3$O$_{\rm 6+x}$ and YBa$_2$Cu$_4$O$_8$ of the quantum critical point which occurs in a model of two antiferromagnetically coupled planes of antiferromagnetically correlated spins. We use a Schwinger boson mean field theory and a scaling analysis to ob...
9311035v1
1998-07-04
Theory for Metal Hydrides with Switchable Optical Properties
Recently it has been discovered that lanthanum, yttrium, and other metal hydride films show dramatic changes in the optical properties at the metal-insulator transition. Such changes on a high energy scale suggest the electronic structure is best described by a local model based on negatively charged hydrogen (H$^-$) i...
9807062v1
1998-12-01
Physical origin of the buckling in CuO$_2$: Electron-phonon coupling and Raman spectra
It is shown theoretically that the buckling of the CuO$_{2}$ planes in certain cuprate systems can be explained in terms of an electric field across the planes which originates from different valences of atoms above and below the plane. This field results also in a strong coupling of the Raman-active out-of-phase vibra...
9812014v1
2003-10-25
Characterization of the electronic properties of YB$_4$ and YB$_6$ using $^{11}$B NMR and first-principles calculations
Two compounds, tetragonal YB$_4$ and cubic YB$_6$, have been investigated by electric-field gradient (EFG) and Knight shift measurements at the boron sites using the $^{11}$B nuclear magnetic resonance (NMR) technique and by performing first-principles calculations. In YB$_6$ $^{11}$B ($I=3/2$) NMR spectra reveal patte...
0310602v1
2005-02-02
Analysis of NMR Spin-Lattice Relaxation Rates in Cuprates
We investigate nuclear spin-lattice relaxation data in the normal state of optimally doped YBaCuO_7 by analyzing the contributions to the relaxation rate of the copper, planar oxygen and yttrium along the directions perpendicular to the applied field. In this new picture there is no contrasting temperature dependence o...
0502075v2
2010-03-09
Dynamical evolution of titanium, strontium, and yttrium spots on the surface of the HgMn star HD 11753
Aims. We gathered about 100 high-resolution spectra of three typical HgMn (mercury-manganese) stars, HD 11753, HD 53244, and HD 221507, to search for slowly pulsating B-like pulsations and surface inhomogeneous distribution of various chemical elements. Methods. Classical frequency analysis methods were used to detect ...
1003.1902v1