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2005-01-28
Magnetic Phase Transition in FeRh
Density functional calculations are performed to investigate the phase transition in FeRh alloy. The effective exchange coupling, the critical temperature of magnetic phase transition and the adiabatic spin wave spectrum have been obtained. Different contributions to the free energy of different phases are estimated. I...
0501701v1
2005-05-12
Incipient magnetism in the cubic perovskites MgCNi3 and YBRh3: A comparison
Using density-functional-based methods, we have studied the effects of incipient magnetism in the cubic perovskites MgCNi_{3} and YBRh_{3} . Our results show that (i) at the equilibrium volume, both MgCNi_{3} and YBRh_{3} alloys remain paramagnetic and (ii) at expanded volumes, only YBRh_{3} shows the possibility of a ...
0505310v1
2005-11-02
Magnetic and electrical characterization of lanthanum superconductors with dilute Lu and Pr impurities
In this work we present measurements of the electrical conductivity and of the magnetization of La and of La-Pr and La-Lu dilute (up to 2 atomic percent) alloys, from which we determine, very in particular, the influence of dilute magnetic impurities on the upper critical magnetic field amplitude [and then on the super...
0511033v1
2006-02-07
Molecular Dynamics and Monte-Carlo Simulations of CoPt alloys
November 2002, "Magister", Supervisors : Dr. H. Bouzar (Tizi-Ouzou, Algeria) with the collaboration of Dr. V. Pierron-Bohnes and Dr. C. Goyhenex (Strasbourg, France). Mouloud Mammeri University, Tizi-Ouzou (Algeria) and Louis Pasteur University, Strasbourg (France).
0602177v2
2006-05-30
Stochastic Green's function approach to disordered systems
Based on distributions of local Green's functions we present a stochastic approach to disordered systems. Specifically we address Anderson localisation and cluster effects in binary alloys. Taking Anderson localisation of Holstein polarons as an example we discuss how this stochastic approach can be used for the invest...
0605731v1
1996-03-21
Expulsion of Magnetic Flux Lines from Growing Superconducting Core of a Quark Star and The Possibility of Mullins-Sekerka Interface Instability
The expulsion of magnetic flux lines from a growing superconducting core of a quark star has been investigated using the idea of impurity diffusion in molten alloys. The possibility of Mullins-Sekerka normal-superconducting interface instability has also been studied.
9603407v1
1998-10-26
Two-Photon Spectroscopy of Transition-Metal Ions in Cubical Symmetry
Symmetry adaptation techniques are applied to the determination of intensities of intra-configurational two-photon transitions for transition-metal ions in cubical symmetry. This leads to a simple model giving the polarization dependence of intensities of two-photon (electric dipolar) transitions between Stark levels o...
9810047v1
2003-01-23
Depleted-Uranium Weapons: the Whys and Wherefores
The only military application in which depleted-uranium (DU) alloys out-perform present-day tungsten alloys is long-rod penetration into a main battle-tank's armor. However, this advantage is only on the order of 10%, and it disappears when the comparison is made in terms of actual lethality of complete anti-tank syste...
0301059v7
2007-05-30
Analysis of long range order
A first principles analysis of order-disorder transition in alloys shows that ordering energy is a function of temperature due to thermal vibrations. The inter-nuclear potential energy term converges if zero point vibrations are incorporated and this method can replace the Ewald sum method. Core energy contributions to...
0705.4382v7
2008-12-14
Wegner-type bounds for a two-particle continuous Anderson model with an alloy-type external potential
We consider a two-particle quantum systems in a d-dimensional Euclidean space with interaction and in presence of a random external potential (a continuous two-particle Anderson model). We establish Wegner-type estimates (inequalities) for such models, assessing the probability that random spectra of Hamiltonians in fi...
0812.2621v1
2009-09-16
AB Percolation in Semiconductor Alloys
We show that, at the percolation threshold, two percolating AB clusters form in the diamond structure simultaneously instead of the usual one in the common site percolation problems. The structure of these two clusters and the related physical properties of semiconductor mixed crystals are discussed.
0909.2922v1
2009-12-09
Exchange interactions and Curie temperatures in Cr-based alloys in Zinc Blende structure: volume- and composition-dependence from first-principles calculations
We present calculations of the exchange interactions and Curie temperatures in Cr-based pnictides and chalcogenides of the form CrX with X=As, Sb, S, Se and Te, and the mixed alloys CrAs$_{50}$X$_{50}$ with X=Sb, S, Se, and Te. The calculations are performed for Zinc Blende (ZB) structure for 12 values of the lattice p...
0912.1760v2
2010-01-10
Electronic origin of superabundant vacancies in Pd hydride under high hydrogen pressures
Formation of a defect face-centered cubic structure containing metal vacancies in Ni-H and Pd-H alloys was observed experimentally at high temperature annealing under high hydrogen pressure. Appearance of vacancies in the fcc structure of the Pd hydride and several other metal hydrides can be accounted for by electroni...
1001.1525v1
2010-07-09
Understanding glassy phenomena in materials
A basis for understanding and modelling glassy behaviour in martensitic alloys and relaxor ferroelectrics is discussed from the perspective of spin glasses.
1007.1530v2
2010-08-18
Contraction and expansion effects on the substitution-defect properties of thirteen alloying elements in bcc Fe
Proposed as blanket structural materials for fusion power reactors, reduced activation ferritic/martensitic (RAFM) steel undergoes volume expanding and contracting in a cyclic mode under service environment. Particularly, being subjected to significant fluxes of fusion neutrons RAFM steel suffers considerable local vol...
1008.3001v1
2011-01-15
On the hardness of boron (III) oxide
Our findings show that the hardness of glass-like B2O3 is of about 1.5 GPa, while the hardness of the high-pressure phase is higher by a factor of 10 (16(5) GPa) and comparable with the hardness (16 GPa) of the WC-10% Co hard alloy.
1101.2965v1
2011-06-03
Interplay between Fe 3d and Ce 4f magnetism and Kondo interaction in CeFeAs_{1-x}P_{x}O probed by ^{75}As and ^{31}P NMR
A detailed $^{31}$P (I=1/2) and $^{75}$As (I=3/2) NMR study on polycrystalline CeFeAs$_{1-x}$P$_{x}$O alloys is presented. The magnetism of CeFeAsO changes drastically upon P substitution on the As site. CeFePO is a heavy fermion system without long range order whereas CeFeAsO exhibits a Fe-3$d$ SDW type of ordering ac...
1106.0652v2
2011-07-01
Defect and solute properties in dilute Fe-Cr-Ni austenitic alloys from first principles
We present results of an extensive set of first-principles density functional theory calculations of point defect formation, binding and clustering energies in austenitic Fe with dilute concentrations of Cr and Ni solutes.
1107.0260v2
2011-08-17
Influence of Steel Alloying Components on Martensite Tetragonality
A formerly developed method aimed at determining the constituents of a merged X-ray pattern doublet was applied to estimate the fact that low-carbon martensite with high concentration of strong carbide-forming elements possesses abnormally small tetragonality(c/a < 1). The article treats the nature of carbide-forming a...
1108.3420v1
2012-04-02
Blends and Alloys
Given two algebras A and B, sometimes assumed to be C*-algebras, we consider the question of putting algebra or C*-algebra structures on the tensor product A\otimes B. In the C*-case, assuming B to be two-dimensonal, we characterize all possible such C*-algebra structures in terms of an action of the cyclic group Z_2. ...
1204.0486v1
2012-05-02
Estimation of the effects of Y and Zn atoms on the elastic properties of Mg solid solution
Mg-based alloys have recently attracted major interest in view of their potential applications in the aerospace, aircraft and automotive industries. Here, we show that the effects of Y and Zn atoms on their compressibility can be reliably estimated by a simple thermodynamical model deduced by means of first-principles ...
1205.0928v1
2012-08-01
Spin-fluctuations in Ti$_{60}$V$_{40}$ alloy and its influence on the superconductivity
We report experimental studies of the temperature and magnetic field dependence of resistivity and dc magnetic susceptibility and the temperature dependence of zero field heat capacity in a Ti$_{0.6}$V$_{0.4}$ alloy. The temperature dependence of the normal state dc magnetic susceptibility in this Ti$_{0.6}$V$_{0.4}$ a...
1208.0181v3
2012-10-29
Spectral statistics for weakly correlated random potentials
We study localization and derive stochastic estimates (in particular, Wegner and Minami estimates) for the eigenvalues of weakly correlated random discrete Schr\"odinger operators in the localized phase. We apply these results to obtain spectral statistics for general discrete alloy type models where the single site pe...
1210.7674v1
2013-01-15
Modified associate formalism without entropy paradox: Part II. Comparison with similar models
The modified associate formalism is compared with similar models, such as the classical associate model, the associate species model and the modified quasichemical model. Advantages of the modified associate formalism are demonstrated.
1301.3215v1
2013-03-05
Impact of alloy disorder on the band structure of compressively strained GaBiAs
The incorporation of bismuth (Bi) in GaAs results in a large reduction of the band gap energy (E$_g$) accompanied with a large increase in the spin-orbit splitting energy ($\bigtriangleup_{SO}$), leading to the condition that $\bigtriangleup_{SO} > E_g$ which is anticipated to reduce so-called CHSH Auger recombination ...
1303.1070v1
2013-11-23
Decorrelation estimates for random discrete Schrödinger operators in dimension one and applications to spectral statistics
The purpose of the present work is to establish decorrelation estimates for some random discrete Schrodinger operator in dimension one. We prove that the Minami estimates are consequences of the Wegner estimates and Localization. We also prove decorrelation estimates at distinct energies for the random hopping model an...
1311.6036v1
2014-07-17
Efficient localization bounds in a continuous multi-particle Anderson model with long-range interaction
We establish strong dynamical localization for a class of multi-particle Anderson models in a Euclidean space with an alloy-type random potential and a sub-exponentially decaying interaction of infinite range. For the first time in the mathematical literature, the uniform decay bounds on the eigenfunction correlators a...
1407.4671v1
2014-09-30
Decorrelation estimates for some continuous and discrete random schrödinger operators in dimension one and applications to spectral statistics
The purpose of the present work is to establish decorrelation estimates at distinct energies for some random Schr\"odinger operator in dimension one. In particular, we establish the result for some random operators on the continuum with alloy-type potential. These results are used to give a description of the spectral ...
1409.8376v1
2014-12-10
Numerical Simulation of Dendritic crystal growth using phase field method and investigating the effects of different physical parameter on the growth of the dendrite
In this journal, we study the phase-field model of solidification for numerical simulation of dendritic crystal growth that occurs during the casting of metals and alloys based on the kobayashi [1] model. Qualitative relationships between shapes of the crystal and physical parameters are studied and visualized.
1412.3197v1
2015-04-28
Segregation, precipitation, and α-α' phase separation in Fe-Cr alloys: a multi-scale modelling approach
Segregation, precipitation, and phase separation in Fe-Cr systems is investigated. Monte Carlo simulations using semiempirical interatomic potential, first-principles total energy calculations, and experimental spectroscopy are used. In order to obtain a general picture of the relation of the atomic interactions and pr...
1504.07576v1
2015-05-22
Decorrelation estimates for some continuous and discrete random Schr{ö}dinger operators in dimension one, without covering condition
The purpose of the present work is to establish decorrelation estimates at distinct energies for some random Schr{\"o}dinger operator in dimension one. In particular, we establish the result for some random operators on the continuum with alloy-type potential without covering condition assumption. These results are use...
1505.06112v1
2015-05-25
On the origin of multi-component bulk metallic glasses: Atomic size mismatches and de-mixing
The critical cooling rate $\mathcal{R}_c$, below which liquids crystallize upon cooling, characterizes the glass-forming ability (GFA) of the system. While pure metals are typically poor glass formers with $\mathcal {R}_c>10^{12}\, {\rm K/s}$, specific multi-component alloys can form bulk metallic glasses (BMGs) even a...
1505.06771v1
2015-06-26
Spin-orbit engineering in transition metal dichalcogenide alloy monolayers
Transition metal dichalcogenide (TMDC) monolayers are newly discovered semiconductors for a wide range of applications in electronics and optoelectronics. Most studies have focused on binary monolayers that share common properties: direct optical bandgap, spin-orbit (SO) splittings of hundreds of meV, light-matter inte...
1506.08114v1
2015-08-24
All-thermal switching of amorphous Gd-Fe alloys: analysis of structural properties and magnetization dynamics
In recent years, there has been an intense interest in understanding the microscopic mechanism of thermally induced magnetization switching driven by a femtosecond laser pulse. Most of the effort has been dedicated to periodic crystalline structures while the amorphous counterparts have been less studied. By using a mu...
1508.05972v1
2015-11-06
Atomic-scale avalanche along a dislocation in a random alloy
The propagation of dislocations in random crystals is evidenced to be governed by atomic-scale avalanches whose the extension in space and the time intermittency characterizingly diverge at the critical threshold. Our work is the very first atomic-scale evidence that the paradigm of second order phase transitions appli...
1511.02051v1
2016-07-26
Maxwell equation violation by density dependent magnetic fields in neutron stars
We show that the widely used density dependent magnetic field prescriptions, necessary to account for the variation of the field intensity from the crust to the core of neutron stars violate one of the Maxwell equations. We estimate how strong the violation is when different equations of state are used and check for wh...
1607.07687v1
2016-11-18
Electronic structure and properties of (TiZrNbCu)_1-xNi_x high entropy amorphous alloys
A comprehensive study of selected properties of four (TiZrNbCu)_1-xNi_x (x \le 0.25) amorphous high entropy alloys (a-HEA) has been performed. The samples were ribbons about 20 \mum thick and their fully amorphous state was verified by X-ray diffraction and thermal analysis. The surface morphology, precise composition ...
1611.06091v1
2017-01-31
Heterodiffusion coefficients in α-iron
The diffusion of tungsten in {\alpha}-iron is important for the application of ferritic-iron alloys to thermal power plants. These data, over a wide temperature range across the Curie temperature, have been recently reported. We show that these diffusion coefficients can be satisfactory reproduced in terms of the bulk ...
1701.08993v1
2017-07-13
The study on quantum material WTe2
WTe2 and its sister alloys have attracted tremendous attentions recent years due to the large non-saturating magnetoresistance and topological non-trivial properties. Herein, we briefly review the electrical property studies on this new quantum material.
1707.04132v1
2017-08-01
Enhanced piezoelectric response of AlN via CrN alloying
Since AlN has emerged as an important piezoelectric material for a wide variety of applications, efforts have been made to increase its piezoelectric response via alloying with transition metals that can substitute for Al in the wurtzite lattice. Herein, we report density functional theory calculations of structure and...
1708.00490v5
2017-09-25
Metastable Phase Diagram and Precipitation Kinetics of Magnetic Nanocrystals in FINEMET Alloys
Research over the years has shown that the formation of the Fe$_3$Si phase in FINEMET (Fe-Si-Nb-B-Cu) alloys leads to superior soft magnetic properties. In this work, we use a CALPHAD approach to derive Fe-Si phase diagrams to identify the composition-temperature domain where the Fe$_3$Si phase can be stabilized. There...
1709.08306v2
2018-01-06
Lithiation of Silicon Anode based on Soft X-ray Emission Spectroscopy: A Theoretical Study
Due to its exceptional lithium storage capacity silicon is considered as a promising candidate for anode material in lithium-ion batteries (LIBs). In the present work we demonstrate that methods of the soft X-ray emission spectroscopy (SXES) can be used as a powerful tool for the comprehensive analysis of the electroni...
1801.01983v1
2018-03-22
Tuning magnetocrystalline anisotropy of Fe$_{3}$Sn by alloying
The electronic structure, magnetic properties and phase formation of hexagonal ferromagnetic Fe$_{3}$Sn-based alloys have been studied from first principles and by experiment. The pristine Fe$_{3}$Sn compound is known to fulfill all the requirements for a good permanent magnet, except for the magnetocrystalline anisotr...
1803.08292v1
2018-11-01
Beyond real space super cell approximation, corrections to the real space cluster approximation
Motion of a single electron in a disordered alloy and or interacting electrons systems such as magnetic materials, strongly correlated systems and superconductors is replaced by motion of that in an effective medium which is denoted by self-energy. The study of disordered alloy and interacting electrons systems based o...
1811.00443v1
2021-07-23
Modeling the dynamical behavior of memristive {NiTi} alloy at constant stress for time-varying electric current input signals
The dynamical electric behavior of a NiTi smart alloy thin filament when driven by time varying current pulses is studied by a structure-based phenomenological model that includes rate-based effects. The simulation model relates the alloy's electrical resistivity to the relative proportions of the three main structural...
2107.11060v1
2017-04-05
Lifshits Tails for Squared Potentials
We consider Schr\"odinger operators with a random potential which is the square of an alloy-type potential. We investigate their integrated density of states and prove Lifshits tails. Our interest in this type of models is triggered by an investigation of randomly twisted waveguides.
1704.01435v3
2017-05-18
Effect of disorder on the optical response of NiPt and Ni$_3$Pt alloys
In this communication we present a detailed study of the effect of chemical disorder on the optical response of Ni$_{1-x}$Pt$_x$ (0.1$\leq$ x $\leq$0.75) and Ni$_{3(1-x)/3}$Pt$_x$ (0.1$\leq$ x $\leq$0.3). We shall propose a formalism which will combine a Kubo-Greenwood approach with a DFT based tight-binding linear muf...
1705.06549v2
2018-07-06
Unexpected behaviour of the crystal growth velocity at the hypercooling limit
The crystal growth velocity is one thermodynamic parameter of solidification experiments of undercooled melts under non-equilibrium conditions, which is directly accessible to observation. We applied the electrostatic levitation technique in order to study the crystal growth velocity $v$ as a function of the undercooli...
1807.02507v3
2018-08-06
Effect of N interstitial complexes on the electronic properties of GaAs$_{1-x}$N$_{x}$ alloys from first principles
Several approaches have been used to investigate the impact of Nitrogen (N) on the electronic structure of GaAs$_{1-x}$N$_{x}$ alloys, however, there is no agreement between theory and experiments about the importance of the different N interstitial defects in these alloys, and their nature is still unknown. Here we an...
1808.02142v3
2020-03-29
Prediction of properties of steel alloys
We present a study of possible predictors based on four supervised machine learning models for the prediction of four mechanical properties of the main industrially used steels. The results were obtained from an experimental database available in the literature which were used as input to train and evaluate the models.
2004.06037v1
2020-08-10
Optical Properties of Dilute CuAl$_{1-x}$Fe$_x$O$_2$ Delafossite Alloys
For powder samples of CuAl$_{1-x}$Fe$_x$O$_2$ ($x =$ 0, 0.01, 0.05, and 0.1), measured optical properties are compared with model simulations and phonon spectra are compared with simulations based on weighted dynamical matrix approach.
2008.04408v2
2021-03-12
Gibbs measures of Potts model on Cayley trees: a survey and applications
In this paper we give a systematic review of the theory of Gibbs measures of Potts model on Cayley trees (developed since 2013) and discuss many applications of the Potts model to real world situations: mainly biology, physics, and some examples of alloy behavior, cell sorting, financial engineering, flocking birds, fl...
2103.07391v1
2022-02-06
An alternative strategy for the use of a low-cost age-hardenable Fe-Si-Ti steel for automotive application
For High Strength Low Alloy (HSLA) steels or for age-hardenable steels (maraging) the strengthening by precipitation is done before forming operation in order to increase the yield stress as much as possible. In this publication the advantages of an hardening thermal treatment after forming operation are investigated i...
2202.02737v1
2022-03-14
Revisiting stress-corrosion cracking and hydrogen embrittlement in 7xxx-Al alloys at the near-atomic-scale
Hydrogen embrittlement (HE) affects all major high-strength structural materials and as such is a major impediment to lightweighting e.g. vehicles and help reduce carbon-emissions and reach net-zero. The high-strength 7xxx series aluminium alloys can fulfil the need for light, high strength materials, and are already e...
2203.07058v1
2017-02-02
Dislocation mediated plastic flow in aluminum: comparison between theory and experiment
The theory of dislocation mediated plastic flow proposed by Langer, Bouchbinder, and Lookman is applied to compute the stress-strain curve of aluminum and aluminum alloys over a wide range of temperatures and strain rates. The comparison with experiment shows excellent agreement.
1702.00663v2
2019-12-19
Specific Heat of Holmium in Gold and Silver at Low Temperatures
The specific heat of dilute alloys of holmium in gold and in silver plays a major role in the optimization of low temperature microcalorimeters with enclosed $^{163}\textrm{Ho}$, such as the ones developed for the neutrino mass experiment ECHo. We investigate alloys with atomic concentrations of $x_\textrm{Ho}=0.01\,\%...
1912.09354v3
2020-02-21
Relaxation and vibrational properties in metal alloys and other disordered systems
The relaxation dynamics and the vibrational spectra of amorphous solids, such as metal alloys, have been intensely investigated as well separated topics in the past. The aim of this review is to summarize recent results in both these areas in an attempt to establish, or unveil, deeper connections between the two phenom...
2002.09397v2
2020-10-18
RBAC for Healthcare-Infrastructure and data storage
Role based Access control (RBAC) is the cornerstone of security for any modern organization. In this report, we defined a health-care access control structure based on RBAC. We used Alloy formal logic modeling tool to model and validate system functions. We modeled system static and dynamic or temporal behaviours. We f...
2010.11096v1
2021-09-21
Proximity-Effect-Induced Anisotropic Superconductivity in Monolayer Ni-Pb Binary Alloy
Proximity effect facilitates the penetration of Cooper pairs that permits superconductivity in normal metal, offerring a promising approach to turn heterogeneous materials into superconducting and develop exceptional quantum phenomena. Here, we have systematically investigated proximity-induced anisotropic superconduct...
2109.09976v1
2021-11-23
Magnetism in Metastable and Annealed Compositionally Complex Alloys
Compositionally complex materials (CCMs) present a potential paradigm shift in the design of magnetic materials. These alloys exhibit long-range structural order coupled with limited or no chemical order. As a result, extreme local environments exist with a large opposing magnetic energy term, which can manifest large ...
2111.12188v1
2022-04-04
Exceptional fracture toughness of CrCoNi-based medium- and high-entropy alloys close to liquid helium temperatures
Medium- and high-entropy alloys based on the CrCoNi-system have been shown to display outstanding strength, tensile ductility and fracture toughness (damage-tolerance properties), especially at cryogenic temperatures. Here we examine the JIc and (back-calculated) KJIc fracture toughness values of the face-centered cubi...
2204.01635v1
2022-11-07
Vapor-liquid-solid growth of highly-mismatched semiconductor nanowires with high-fidelity van der Waals layer stacking
Nanobelts, nanoribbons and other quasi-one-dimensional nanostructures formed from layered, so-called, van der Waals semiconductors have garnered much attention due to their high-performance, tunable optoelectronic properties. For layered alloys made from the gallium monochalcogenides GaS, GaSe, and GaTe, near-continuou...
2211.03366v1
2022-11-07
Structure and solidification of the (Fe0.75B0.15Si0.1)100-xTax (x=0-2) melts: experiment and machine learning
Fe-B-Si system is a matrix for synthesis of new functional materials with exceptional magnetic and mechanical properties. Progress in this area is associated with the search for optimal doping conditions. This theoretical and experimental study is aimed to address the influence of Ta alloying on the structure of underc...
2211.03500v1
2023-05-19
Machine Learning Moment Tensor Potential for Modelling Dislocation and Fracture in L1$_0$-TiAl and D0$_{19}$-Ti$_3$Al Alloys
Dual-phase $\gamma$-TiAl and $\alpha_2$-Ti$_{3}$Al alloys exhibit high strength and creep resistance at high temperatures. However, they suffer from low tensile ductility and fracture toughness at room temperature. Experimental studies show unusual plastic behaviour associated with ordinary and superdislocations, makin...
2305.11825v2
2023-06-12
Binary nanocrystalline alloys with strong glass forming interfacial regions: Complexion stability, segregation competition, and diffusion pathways
Stabilization of grain structure is important for nanocrystalline alloys, and grain boundary segregation is a common approach to restrict coarsening. Doping can alter grain boundary structure, with high temperature states such as amorphous complexions being particularly promising for stabilization. Dopant enrichment at...
2306.07410v2
2023-06-24
High Strength Refractory AlHfNbTiV B2 High Entropy Alloys with High Fracture Strains
We demonstrate the development of a series of refractory high-entropy alloys containing aluminum AlRHEAs in the ordered BCC-B2 phase by varying the aluminum content within 10 to 25 atomic percent, with the goal of high strength and good ductility synergy. The AlRHEAs obtained are found to show promising potential for h...
2306.14057v2
2023-07-11
Structural and magnetic properties of Fe-Co-C alloys with tetragonal deformation: a first-principle study
Fe-Co alloys with induced tetragonal strain are promising materials for rare-earth-free permanent magnets. However, as ultrathin-film studies have shown, tetragonal Fe-Co structures tend to a rapid relaxation toward a cubic structure as the thickness of the deposited film increases. One of the main methods of inducing ...
2307.05709v1
2023-08-15
Explainable Machine Learning for Hydrogen Diffusion in Metals and Random Binary Alloys
Hydrogen diffusion in metals and alloys plays an important role in the discovery of new materials for fuel cell and energy storage technology. While analytic models use hand-selected features that have clear physical ties to hydrogen diffusion, they often lack accuracy when making quantitative predictions. Machine lear...
2308.07823v2
2023-09-23
Resonant band hybridization in alloyed transition metal dichalcogenide heterobilayers
Bandstructure engineering using alloying is widely utilised for achieving optimised performance in modern semiconductor devices. While alloying has been studied in monolayer transition metal dichalcogenides, its application in van der Waals heterostructures built from atomically thin layers is largely unexplored. Here,...
2309.13312v1
2023-11-08
General-purpose machine-learned potential for 16 elemental metals and their alloys
Machine-learned potentials (MLPs) trained against quantum-mechanical reference data have demonstrated remarkable accuracy, surpassing empirical potentials. However, the absence of readily available general-purpose MLPs encompassing a broad spectrum of elements and their alloys hampers the applications of MLPs in materi...
2311.04732v1
2024-01-29
AnisoGNN: graph neural networks generalizing to anisotropic properties of polycrystals
We present AnisoGNNs -- graph neural networks (GNNs) that generalize predictions of anisotropic properties of polycrystals in arbitrary testing directions without the need in excessive training data. To this end, we develop GNNs with a physics-inspired combination of node attributes and aggregation function. We demonst...
2401.16271v1
2006-11-23
Half-Metallic Graphene Nanoribbons
Electrical current can be completely spin polarized in a class of materials known as half-metals, as a result of the coexistence of metallic nature for electrons with one spin orientation and insulating for electrons with the other. Such asymmetric electronic states for the different spins have been predicted for some ...
0611600v1
2006-12-07
Influence of mixing the low-valent transition metal atoms (Y,Y$^*$=Cr,Mn,Fe) on the properties of the quaternary Co$_2$[Y$_{1-x}$Y$^*_x$]Z (Z=Al,Ga,Si,Ge,Sn) Heusler compounds
We complement our study on the doping and disorder in Co$_2$MnZ compounds [I. Galanakis \textit{et al.}, Appl. Phys. Lett. \textbf{89}, 042502 (2006) and K. \"Ozdo\~gan \textit{et al.}, Phys. Rev. B \textbf{74}, (2006)] to cover also the quaterarny Co$_2$[Y$_{1-x}$Y$^*_x$]Z compounds with the lower-valent transition me...
0612194v1
1994-10-27
Band gap and stability in the ternary intermetallic compounds NiSnM (M = Ti, Zr, Hf): A first principles study
The structural stability and electronic properties of the ternary intermetallic compounds NiSnM (M = Ti, Zr, Hf) and the closely related Heusler compounds Ni$_2$SnM are discussed using the results of ab initio pseudopotential total energy and band-structure calculations performed with a plane wave basis set using the c...
9411001v2
2011-06-24
Magnetic dichroism in angular-resolved hard X-ray photoelectron spectroscopy from buried layers
This work reports the measurement of magnetic dichroism in angular-resolved photoemission from in-plane magnetized buried thin films. The high bulk sensitivity of hard X-ray photoelectron spectroscopy (HAXPES) in combination with circularly polarized radiation enables the investigation of the magnetic properties of bur...
1106.4976v1
2011-11-28
Reduction of spin polarization by incoherent tunneling in Co2FeAl/MgO/CoFe magnetic tunnel junctions with thick MgO barriers
We report on spin polarization reduction by incoherent tunneling in realistic single crystal Co2FeAl/MgO/Co50Fe50 magnetic tunnel junctions (MTJ) compared to reference Fe/MgO/Fe. A large density of misfit dislocations in the Heusler based MTJs has been insured by a thick MgO barrier and its 3.8% lattice mismatch with t...
1111.6442v3
2012-01-30
Insights into the electronic structure of Co2FeSi from x-ray magnetic linear dichroism
Experimental evidence both for and against a half-metallic ground-state of the Heusler compound Co2FeSi has been published. Density functional theory based calculations suggest a non half-metallic ground state. It has been argued, that on-site Coulomb interaction of the d electrons has to be taken into account via the ...
1201.6263v2
2012-03-13
Stabilization of Majorana modes in vortices in the superconducting phase of topological insulators using topologically trivial bands
If superconductivity is induced in the metallic surface states of topological insulators via proximity, Majorana modes will be trapped on the vortex cores. The same effects hold for doped topological insulators which become bulk s-wave superconductors as long as the doping does not exceed a critical values $ \mu^{\pm}_...
1203.2958v2
2013-11-21
Effect of annealing on spinodally decomposed Co2CrAl grown via floating zone technique
Among the large class of Heusler compounds, Co2CrAl is predicted to be 100 % spin polarized and is hence, a potential candidate for application in spintronics. So far, the predicted properties have not been experimentally realized which may be attributed to the phase segregated nature of samples. This phase segregation...
1311.5453v1
2014-01-17
Co2FeAl Heusler thin films grown on Si and MgO substrates: annealing temperature effect
10 nm and 50 nm Co$_{2}$FeAl (CFA) thin films have been deposited on MgO(001) and Si(001) substrates by magnetron sputtering and annealed at different temperatures. X-rays diffraction revealed polycrystalline or epitaxial growth (according to the relation CFA(001)[110]//MgO(001)[100] epitaxial relation), respectively f...
1401.4397v1
2014-05-19
Low-Dimensional Transport and Large Thermoelectric Power Factors in Bulk Semiconductors by Band Engineering of Highly Directional Electronic States
Thermoelectrics are promising to address energy issues but their exploitation is still hampered by low efficiencies. So far, much improvement has been achieved by reducing the thermal conductivity but less by maximizing the power factor. The latter imposes apparently conflicting requirements on the band structure: a na...
1405.4685v3
2015-01-16
State of Co and Mn in half-metallic ferromagnet Co$_2$MnSi explored by magnetic circular dichroism in hard X-ray photoelectron emission and soft X-ray absorption spectroscopies
The half-metallic Heusler compound Co$_2$MnSi is a very attractive material for spintronic devices because it exhibits very high tunnelling magnetoresistance ratios. This work reports on a spectroscopic investigation of thin Co$_2$MnSi films as they are used as electrodes in magnetic tunnel junctions. The investigated ...
1501.03966v1
2015-10-01
Creating Nanostructured Superconductors On Demand by Local Current Annealing
Superconductivity results from a Bose condensate of Cooper-paired electrons with a macroscopic quantum wavefunction. Dramatic effects can occur when the region of the condensate is shaped and confined to the nanometer scale. Recent progress in nanostructured superconductors has revealed a route to topological supercond...
1510.00362v1
2016-08-05
Ternary Semiconductors NiZrSn and CoZrBi with half-Heusler structure: a first-principles study
The ternary semiconductors NiZrSn and CoZrBi with C1_b crystal structure are introduced by calculating their basic structural, electronic and phononic properties using density functional theory. Both the gradient-corrected PBE functional and the hybrid functional HSE06 are employed. While NiZrSn is found to be a small-...
1608.01957v1
2016-11-28
Synthesis of low-moment CrVTiAl: a potential room temperature spin filter
The efficient production of spin-polarized currents at room temperature is fundamental to the advancement of spintronics. Spin-filter materials --- semiconductors with unequal band gaps for each spin channel --- can generate spin-polarized current without the need for spin-polarized contacts. In addition, a spin-filter...
1611.09307v3
2017-07-11
Unconventional Superconductivity in Luttinger Semimetals: Theory of Complex Tensor Order and the Emergence of the Uniaxial Nematic State
We investigate unconventional superconductivity in three-dimensional electronic systems with the chemical potential close to a quadratic band touching point in the band dispersion. Short-range interactions can lead to d-wave superconductivity, described by a complex tensor order parameter. We elucidate the general stru...
1707.03444v2
2017-07-26
Studying the effect of different exchange correlation functionals on the structural and electronic properties of a half-Heusler NaAuS compound
Theoretically, NaAuS is predicted as topological insulator, while no detail electronic structure study has been done for this compound. Here, we report the structural and electronic properties of NaAuS by using LDA, PBEsol, PBE and revPBE exchange correlation functionals. The calculated values of equilibrium lattice co...
1707.08457v1
2017-09-13
Pairing states of spin-3/2 fermions: Symmetry-enforced topological gap functions
We study the topological properties of superconductors with paired $j=\frac{3}{2}$ quasiparticles. Higher spin Fermi surfaces can arise, for instance, in strongly spin-orbit coupled band-inverted semimetals. Examples include the Bi-based half-Heusler materials, which have recently been established as low-temperature an...
1709.04487v2
2017-11-30
Topological Hopf and chain link semimetal states and their application to Co2MnGa (Theory and Materials Prediction)
Topological semimetals can be classified by the connectivity and dimensionality of the band cross- ing in momentum space. The band crossings of a Dirac, Weyl, or an unconventional fermion semimet- al are 0D points, whereas the band crossings of a nodal-line semimetal are 1D closed loops. Here we propose that the presen...
1712.00055v1
2018-05-16
Thermoelectric Alchemy: Designing A Chemical Analog to PbTe with Intrinsic High Band Degeneracy and Low Lattice Thermal Conductivity
Improving the figure of merit $zT$ of thermoelectric materials requires simultaneously a high power factor and low thermal conductivity. An effective approach for increasing the power factor is to align the band extremum and achieve high band degeneracy ($\geq$ 12) near the Fermi level as realized in PbTe [\textcolor{b...
1805.06433v1
2018-06-18
AFLOW-CHULL: Cloud-oriented platform for autonomous phase stability analysis
$\textit{A priori}$ prediction of phase stability of materials is a challenging practice, requiring knowledge of all energetically-competing structures at formation conditions. Large materials repositories $\unicode{x2014}$ housing properties of both experimental and hypothetical compounds $\unicode{x2014}$ offer a pat...
1806.06901v1
2018-09-19
Exploring the best scenario for understanding the high temperature thermoelectric behaviour of Fe2VAl
Heusler-type Fe2VAl compound is a promising thermoelectric candidate with non-magnetic ground state. The present work investigates the Seebeck coefficient (S) of Fe2VAl in the temperature region 300 to 620 K with the help of experimental and theoretical tools. The experimental value of S is observed -130 {\mu}V/K at 30...
1809.07015v1
2018-11-09
Topological d+s wave superconductors in a multi-orbital quadratic band touching system
Realization of topological superconductors is one of the most important goals in studies of topological phases in quantum materials. In this work, we theoretically propose a novel way to attain topological superconductors with non-trivial Fermi surfaces of Bogoliubov quasiparticles. Considering the interacting Luttinge...
1811.04046v1
2018-11-12
Large anomalous Hall and Nernst effect from nodal line symmetry breaking in Fe$_2$MnX (X=P,As,Sb)
A large Berry curvature in the vicinity of the Fermi energy is required in order to obtain a large anomalous Hall and Nernst effect. This Berry curvature can be induced by Weyl points and gapped nodal lines. One of the possible mechanisms takes place in systems with a symmetry group where mirror planes lead to protecte...
1811.04680v1
2019-11-13
Thermoelectric properties, efficiency and thermal expansion of ZrNiSn half-Heusler by first-principles calculations
In this work, we try to understand the experimental thermoelectric (TE) properties of a ZrNiSn sample with DFT and semiclassical transport calculations using SCAN functional. SCAN and mBJ provide the same band gap $E_{g}$ of $\sim$0.54 eV. This $E_{g}$ is found to be inadequate to explain the experimental data. The bet...
1911.05680v1
2020-01-28
Anomalous transverse response of Co$_2$MnGa and universality of the room-temperature $α^A_{ij}/σ^A_{ij}$ ratio across topological magnets
The off-diagonal (electric, thermal and thermoelectric) transport coefficients of a solid can acquire an anomalous component due to the non-trivial topology of the Bloch waves. We present a study of the anomalous Hall (AHE), Nernst (ANE) and thermal Hall effects (ATHE) in the Heusler Weyl ferromagnet Co$_2$MnGa. The An...
2001.10264v1
2018-07-06
Strategic enhancement of anomalous Nernst effect in Co2MnAl1-xSix Heusler compounds
The anomalous Nernst effect (ANE), a thermoelectric phenomenon in magnetic materials, has potential for novel energy harvesting applications because its orthogonal relationship between the temperature gradient and the electric field enables us to utilize the large area of non-flat heat sources. In this study, the requi...
1807.02209v3
2018-07-12
Giant anomalous Nernst effect and quantum-critical scaling in a ferromagnetic semimetal
In metallic ferromagnets, the Berry curvature of underlying quasiparticles can cause an electric voltage perpendicular to both magnetization and an applied temperature gradient, a phenomenon called the anomalous Nernst effect (ANE). Here, we report the observation of a giant ANE in the full-Heusler ferromagnet Co$_2$Mn...
1807.04761v1
2018-07-17
Large anomalous Nernst effect in thin films of the Weyl semimetal Co2MnGa
The magneto-thermoelectric properties of Heusler compound thin films are very diverse. Here, we discuss the anomalous Nernst response of Co$_2$MnGa thin films. We systematically study the anomalous Nernst coefficient as a function of temperature, and we show that unlike the anomalous Hall effect, the anomalous Nernst e...
1807.06487v1
2018-07-20
Characterization of topological band structures away from the Fermi level by anomalous Nernst measurements
Resolving the structure of energy bands in transport experiments is a major challenge in condensed matter physics and material science. Sometimes, however, traditional electrical conductance or resistance measurements only provide very small signals, and thus limit the ability to obtain direct band structure informatio...
1807.07843v1