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2020-02-07
Assessment of GaPSb/Si tandem material association properties for photoelectrochemical cells
Here, the structural, electronic and optical properties of the GaP1-xSbx/Si tandem materials association are determined in view of its use for solar water splitting applications. The GaPSb crystalline layer is grown on Si by Molecular Beam Epitaxy with different Sb contents. The bandgap value and bandgap type of GaPSb ...
2002.02774v1
2020-02-08
Liquid-phase reinforced Metal matrix (LMM) composite with non-intuitive properties
Over the ages, efforts have been made to use composite design to reinforce metals and alloys in order to increase their strength and modulus. On the other hand, nature herself improves the strength, ductility, stiffness and toughness of materials by strengthening them with liquids having zero strength/modulus. Here, em...
2002.03151v1
2020-02-20
Preparation and Characterization of High-Entropy Alloy (TaNb)$_{1-x}$(ZrHfTi)$_x$ Superconducting Films
We report on the preparation and the physical properties of superconducting (TaNb)_1-x(ZrHfTi)_x high-entropy alloy films. The films were prepared by means of magnetron sputtering at room temperature, with x ranging from 0 to 1 with an average thickness of 600 - 950 nm. All films crystallize in a pseudo body-centered c...
2002.08714v1
2020-03-11
Temporally resolved LEIS measurements of Cr segregation after preferential sputtering of WCrY alloy
The dynamic behaviour of thermally driven segregation of Cr to the surface of WCrY smart alloy is studied with low energy ion scattering (LEIS). Sputtering the WCrY sample with 500 eV D$_2^+$ ions at room temperature results in preferential removal of the lighter alloy constituents and causes an almost pure W surface l...
2003.05343v2
2020-04-14
Compositional gradients in sputtered Ti-Au alloys: Site-selective Au-decoration of anodic TiO$_2$ nanotubes towards enhanced photocatalytic H$_2$ evolution
Au nanoparticles at the TiO$_2$ surface can enhance the photocatalytic H$_2$ generation performances owing to their electron transfer co-catalytic ability. Key to maximize the co-catalytic effect is a fine control over Au nanoparticle size and placement on the photocatalyst, in relation to parameters such as the TiO$_2...
2006.02851v1
2020-06-16
In situ and Operando X-ray Imaging of Directed Energy Deposition Additive Manufacturing
The mechanical performance of Directed Energy Deposition Additive Manufactured (DED-AM) components can be highly material dependent. Through in situ and operando synchrotron X-ray imaging we capture the underlying phenomena controlling build quality of stainless steel (SS316) and titanium alloy (Ti6242 or Ti-6Al-2Sn-4Z...
2006.09087v1
2020-07-14
Cyclic plasticity and fatigue damage of CrMnFeCoNi high entropy alloy fabricated by laser powder-bed fusion
The CrMnFeCoNi high-entropy alloy is highly printable and holds great potential for structural applications. However, no significant discussions on cyclic plasticity and fatigue damage in previous studies. This study provides significant insights into the link between print processes, solidification microstructure, cyc...
2007.07043v1
2020-07-29
Reinvestigation of the intrinsic magnetic properties of (Fe$_{1-x}$Co$_x$)$_2$B alloys and crystallization behavior of ribbons
New determination of the magnetic anisotropy from single crystals of (Fe$_{1-x}$Co$_x$)$_2$B alloys are presented. The anomalous temperature dependence of the anisotropy constant is discussed using the standard Callen-Callen theory, which is shown to be insufficient to explain the experimental results. A more material ...
2007.15113v1
2020-09-07
Tuneable Correlated Disorder in Alloys
Understanding the role of disorder and the correlations that exist within it, is one of the defining challenges in contemporary materials science. However, there are few material systems, devoid of other complex interactions, which can be used to systematically study the effects of crystallographic conflict on correlat...
2009.03226v3
2020-09-10
Spin waves in alloys at finite temperatures: application for FeCo magnonic crystal
We study theoretically the influence of the temperature and disorder on the spin wave spectrum of the magnonic crystal Fe$_{1-c}$Co$_{c}$. Our formalism is based on the analysis of a Heisenberg Hamiltonian by means of the wave vector and frequency dependent transverse magnetic susceptibility. The exchange integrals ent...
2009.04712v6
2020-09-23
Solute-point defect interactions, coupled diffusion, and radiation induced segregation in fcc nickel
Radiation-induced segregation (RIS) of solutes in materials exposed to irradiation is a well-known problem. It affects the life-time of nuclear reactor core components by favouring radiation-induced degradation phenomena such as hardening and embrittlement. In this work, RIS tendencies in face-centered cubic (fcc) Ni-X...
2009.11132v1
2020-10-15
Visualizing the multifractal wavefunctions of a disordered two-dimensional electron gas
The wavefunctions of a disordered two-dimensional electron gas at the quantum-critical Anderson transition are predicted to exhibit multifractal scaling in their real space amplitude. We experimentally investigate the appearance of these characteristics in the spatially resolved local density of states of a two-dimensi...
2010.07554v1
2020-10-16
Synthesis of narrow SnTe nanowires using alloy nanoparticles
Topological crystalline insulator tin telluride (SnTe) provides a rich playground to examine interactions of correlated electronic states, such as ferroelectricity, topological surface states, and superconductivity. Making SnTe into nanowires further induces novel electronic states due to one-dimensional (1D) confineme...
2010.08078v1
2020-11-25
Indirect to direct band gap crossover in two-dimensional WS2(1-x)Se2x alloys
In atomically thin transition metal dichalcogenide semiconductors, there is a crossover from indirect to direct bandgap as the thickness drops to one monolayer, which comes with a fast increase of the photoluminescence signal. Here, we show that for different alloy compositions of WS2(1-x)Se2x this trend may be signifi...
2011.12587v1
2020-12-01
Fundamental hydrogen storage properties of TiFe-alloy with partial substitution of Fe by Ti and Mn
TiFe intermetallic compound has been extensively studied, owing to its low cost, good volumetric hydrogen density, and easy tailoring of hydrogenation thermodynamics by elemental substitution. All these positive aspects make this material promising for large-scale applications of solid-state hydrogen storage. On the ot...
2012.00354v2
2020-12-05
Elastic Properties and Glass Forming Ability of the Zr$_{50}$Cu$_{40}$Ag$_{10}$ Metallic Alloy
The elastic properties of the Zr$_{50}$Cu$_{40}$Ag$_{10}$ metallic alloy, such as the bulk modulus $B$, the shear modulus $G$, the Young's modulus $E$ and the Poisson's ratio $\sigma$, are investigated by molecular dynamics simulation in the temperature range $T=250-2000$ K and at an external pressure of $p = 1.0$ bar....
2012.03109v1
2020-12-17
Unconventional critical behaviour in weak ferromagnets Fe2-xMnxCrAl (0<x<1)
Recent studies on weak ferromagnets Fe2-xMnxCrAl (0<x<1) reveal the presence of cluster glass (CG) and Griffiths phase (GP) below and above the ferromagnetic transition temperature (TC) [(2019) Sci. Rep. 9 15888]. In this work, the influence of these inhomogeneous phases on the critical behaviour (around TC) of the abo...
2012.09453v1
2021-02-04
Interfacial Tension Modulation of Liquid Metal via Electrochemical Oxidation
This progress report summarizes recent studies of electrochemical oxidation to modulate the interfacial tension of gallium-based alloys. These alloys, which are liquid at ambient conditions, have the largest interfacial tension of any liquid at room temperature. The ability to modulate the tension offers the possibilit...
2102.02383v1
2021-02-04
Quantum Transport in Two-Dimensional WS$_2$ with High-Efficiency Carrier Injection Through Indium Alloy Contacts
Two-dimensional transition metal dichalcogenides (TMDCs) have properties attractive for optoelectronic and quantum applications. A crucial element for devices is the metal-semiconductor interface. However, high contact resistances have hindered progress. Quantum transport studies are scant as low-quality contacts are i...
2102.02489v1
2021-02-17
Origin of negative anomalous Nernst thermopower in Mn-Ga ordered alloys
The negative sign of the anomalous Nernst thermopower ($S_\text{ANE}$) observed in Mn-Ga ordered alloys is an attractive property for thermoelectric applications exploiting the anomalous Nernst effect (ANE); however, its origin has not been clarified. In this study, to gain insight into the negative $S_\text{ANE}$, we ...
2102.08625v1
2021-02-19
Quantifying multi-point ordering in alloys
A central problem in multicomponent lattice systems is to systematically quantify multi-point ordering. Ordering in such systems is often described in terms of pairs, even though this is not sufficient when three-point and higher-order interactions are included in the Hamiltonian. Current models and parameters for mult...
2102.10010v2
2021-02-19
FLACK: Counterexample-Guided Fault Localization for Alloy Models
Fault localization is a practical research topic that helps developers identify code locations that might cause bugs in a program. Most existing fault localization techniques are designed for imperative programs (e.g., C and Java) and rely on analyzing correct and incorrect executions of the program to identify suspici...
2102.10152v1
2021-05-18
On the role of boron, carbon and zirconium on hot cracking and creep resistance of additively manufactured polycrystalline superalloys
We investigate the hot cracking susceptibility and creep resistance of three versions of a nickel-based superalloy with different contents of boron, carbon and zirconium fabricated by laser powder bed fusion. Crack-free and creep resistant components are achieved for alloys with boron, carbon and no zirconium. We then ...
2105.08307v1
2021-05-20
Three-dimensional modeling of minority-carrier lateral diffusion length including random alloy fluctuations in (In,Ga)N and (Al,Ga)N single quantum wells
For nitride-based InGaN and AlGaN quantum well (QW) LEDs, the potential fluctuations caused by natural alloy disorders limit the lateral intra-QW carrier diffusion length and current spreading. The diffusion length mainly impacts the overall LED efficiency through sidewall nonradiative recombination, especially for $\m...
2105.09538v2
2021-06-15
Bayesian Optimization of High-Entropy Alloy Compositions for Electrocatalytic Oxygen Reduction
Active, selective and stable catalysts are imperative for sustainable energy conversion, and engineering materials with such properties are highly desired. High-entropy alloys (HEAs) offer a vast compositional space for tuning such properties. Too vast, however, to traverse without the proper tools. Here, we report the...
2106.08212v1
2021-06-30
Thermal conductivity of intercalation, conversion, and alloying lithium-ion battery electrode materials as function of their state of charge
Upon insertion and extraction of lithium, materials important for electrochemical energy storage can undergo changes in thermal conductivity (${\Lambda}$) and elastic modulus ($\it M$). These changes are attributed to evolution of the intrinsic thermal carrier lifetime and interatomic bonding strength associated with s...
2106.16040v2
2021-08-02
Crystallography of the martensitic transformation between Ni2In-type hexagonal and TiNiSi-type orthorhombic phases
MnMX (M = Co or Ni, X = Si or Ge) alloys, experiencing structural transformation between Ni2In-type hexagonal and TiNiSi-type orthorhombic phases, attract considerable attention due to their potential applications as room-temperature solid refrigerants. Although lots of studies have been carried out on how to tune this...
2108.00666v1
2021-08-20
Impact of band-anticrossing on band-to-band tunneling in highly-mismatched semiconductor alloys
We theoretically analyse band-to-band tunneling (BTBT) in highly-mismatched, narrow-gap dilute nitride and bismide alloys, and quantify the impact of the N- or Bi-induced perturbation of the band structure -- due to band-anticrossing (BAC) with localised impurity states -- on the electric field-dependent BTBT generatio...
2108.09328v1
2021-09-27
The electrical conductivity of cubic (In$_{1-x}$Ga$_x$)$_2$O$_3$ films ($x\le0.18$): Native point defects, Sn-doping, and the surface electron accumulation layer
The alloying of the group-III transparent semiconducting sesquioxides In$_2$O$_3$ and Ga$_2$O$_3$ can lead to a modulation of the properties of the parent compounds, e.g., the shallow- and deep-donor character of the oxygen vacancy or the presence and absence of a surface electron accumulation layer, respectively. In t...
2109.12875v1
2021-09-27
Molecular Dynamic Characteristic Temperatures for Predicting Metallic Glass Forming Ability
We explore the use of characteristic temperatures derived from molecular dynamics to predict aspects of metallic Glass Forming Ability (GFA). Temperatures derived from cooling curves of self-diffusion, viscosity, and energy were used as features for machine learning models of GFA. Multiple target and model combinations...
2109.13342v1
2021-09-30
Physical and Mechanical Properties of Cu-Fe System Functionally Graded and Multimaterial Structures after the DED
This paper is devoted to experimental characterisation of linear thermal expansion coefficient (LTEC) and mechanical characteristics of the laser deposited Cu-Fe system multilayer functionally graded (FG) structures and binary Cu-Fe alloys, fabricated from the tin, aluminium, and chromium bronze with 89-99 wt.% of copp...
2110.00103v1
2021-10-07
Sudoku-Inspired High-Shannon-Entropy Alloys
Current definition of high-entropy alloys (HEAs) is commonly based on the configurational entropy. But this definition depends only on the chemical composition of a HEA and therefore cannot distinguish the information content that is encoded in various local atomic arrangements and measurable by the Shannon entropy in ...
2110.03797v1
2021-10-19
Effect of alloying and microstructure on formability of advanced high-strength steels processed via quenching and partitioning
The article focuses on the effect of alloying and microstructure on formability of advanced high strength steels (AHSSs) processed via quenching and partitioning (Q&P). Three different Q&P steels with different combination of alloying elements and volume fraction of retained austenite are subjected to uniaxial tensile ...
2110.09818v1
2021-12-13
Wigner-Weyl description of light absorption in disordered semiconductor alloys using the localization landscape theory
The presence of disorder in semiconductors can dramatically change their physical properties. Yet, models faithfully accounting for it are still scarce and computationally inefficient. We present a mathematical and computational model able to simulate the optoelectronic response of semiconductor alloys of several tens ...
2112.06485v2
2021-12-20
Understanding the role of anharmonic phonons in diffusion of bcc metal
Diffusion in high-temperature bcc phase of IIIB-IVB metals such as Zr, Ti, and their alloys is observed to be orders of magnitude higher than bcc metals of group VB-VIB, including Cr, Mo, and W. The underlying reason for this higher diffusion is still poorly understood. To explain this observation, we compare the first...
2112.10866v1
2022-04-01
THz emission from Fe/Pt spintronic emitters with L1$_{0}$-FePt alloyed interface
Recent developments in nanomagnetism and spintronics have enabled the use of ultrafast spin physics for terahertz (THz) emission. Spintronic THz emitters, consisting of ferromagnetic FM / non-magnetic (NM) thin film heterostructures, have demonstrated impressive properties for the use in THz spectroscopy and have great...
2204.00704v1
2022-04-29
Structural and electronic properties of the random alloy ZnSe$_x$S$_{1-x}$
In this article we employ density functional theory in the generalized gradient approximation to investigate the structural and electronic properties of the solid solution alloy $\text{Zn}\text{Se}_x\text{S}_{1-x}$ in the wurtzite structure. We analyzed the character of the bond lengths and angles at the atomic scale, ...
2204.13865v1
2022-06-19
Mo-Si-B alloys for ultra-high temperature space and ground applications: liquid assisted fabrication under various temperature and time conditions
Boron-doped molybdenum silicides have been already recognized as attractive candidates for space and ground ultra-high temperature applications far beyond limits of state-of-the-art nickel based superalloys. In this work, we are exploring a new method for fabricating Mo-Si-B alloys (as coatings or small bulk components...
2206.09464v1
2022-06-23
Atomic ordering and phase separation in lateral heterostructures and multijunctions of ternary two-dimensional hexagonal materials
The growth and microstructural properties of ternary monolayers of two-dimensional hexagonal materials are examined, including both individual two-dimensional crystalline grains and in-plane heterostructures, multijunctions, or superlattices. The study is conducted through the development of a ternary phase field cryst...
2206.11455v1
2022-06-30
High performance Broadband Photodetection Based on Graphene -- MoS$_{2x}$Se$_{2(1-x)}$ Alloy Engineered Phototransistors
The concept of alloy engineering has emerged as a viable technique towards tuning the bandgap as well as engineering the defect levels in two-dimensional transition metal dichalcognides (TMDC). Possibility to synthesize these ultrathin TMDC materials through chemical route has opened realistic possibilities to fabricat...
2206.15032v1
2022-07-12
Phase transformation-induced superconducting aluminium-silicon alloy rings
The development of a materials platform that exhibits both superconducting and semiconducting properties is an important endeavour for a range of emerging quantum technologies. We investigate the formation of superconductivity in nanowires fabricated with silicon-on-insulator (SOI). Aluminium from deposited contact ele...
2207.05343v1
2022-06-02
A mechanically strong and ductile soft magnet with extremely low coercivity
Soft magnetic materials (SMMs) serve in electrical applications and sustainable energy supply, allowing magnetic flux variation in response to changes in applied magnetic field, at low energy loss1. The electrification of transport, households and manufacturing leads to an increase in energy consumption due to hysteres...
2207.05686v1
2022-08-19
Tuning the Magnetic Properties of the CrMnFeCoNi Cantor Alloy
Magnetic properties of more than twenty Cantor alloy samples of varying composition were investigated over a temperature range of 5 K to 300 K and in fields of up to 70 kOe using magnetometry and muon spin relaxation. Two transitions are identified: a spin-glass-like transition that appears between 55 K and 190 K depen...
2208.09537v1
2022-08-23
Hydrogen in Disordered Titania: Connecting Local Chemistry, Structure, and Stoichiometry through Accelerated Exploration
Hydrogen incorporation in native surface oxides of metal alloys often controls the onset of metal hydriding, with implications for materials corrosion and hydrogen storage. A key representative example is titania, which forms as a passivating layer on a variety of titanium alloys for structural and functional applicati...
2208.10956v1
2022-08-24
Chemical order transitions within extended interfacial segregation zones in NbMoTaW
Interfacial segregation and chemical short-range ordering influence the behavior of grain boundaries in complex concentrated alloys. In this study, we use atomistic modeling of a NbMoTaW refractory complex concentrated alloy to provide insight into the interplay between these two phenomena. Hybrid Monte Carlo and molec...
2208.11758v2
2022-09-07
Machine Learning for High-entropy Alloys: Progress, Challenges and Opportunities
High-entropy alloys (HEAs) have attracted extensive interest due to their exceptional mechanical properties and the vast compositional space for new HEAs. However, understanding their novel physical mechanisms and then using these mechanisms to design new HEAs are confronted with their high-dimensional chemical complex...
2209.03173v1
2022-09-19
Effect of Sn on generalized stacking fault energy surfaces in zirconium and its hydrides
Hydrogen embrittlement in Zr alloy fuel cladding is a primary safety concern for water based nuclear reactors. Here we investigated the stabilisation of planar defects within the forming hydrides by Sn, the primary alloying element of Zircaloy-4 used in the cladding. In order to explain formation of hydrides and planar...
2209.09147v1
2022-10-06
Internal or external magma oceans in the earliest protoplanets -- perspectives from nitrogen and carbon fractionation
When the extent of protoplanetary melting approached magma ocean (MO)-like conditions, alloy melts efficiently segregated from the silicates to form metallic cores. The nature of the MO of a differentiating protoplanet, i.e., internal or external MO (IMO or EMO), not only determines the abundances of life-essential vol...
2210.03237v1
2022-10-19
Evolution of local atomic structure accompanying devitrification of amorphous Ni-Zr alloy thin films
Thin film metallic glasses undergoing devitrification can form partially crystallized or fully crystallized materials with novel structural and magnetic properties. The development of desired and tunable properties of such systems drives the need to understand the mechanism of their thermal evolution at the atomic leve...
2210.10399v1
2022-10-27
The criterion of planar instability in alloy solidification under varying conditions: A viewpoint from free energy
In alloy solidification, the transport processes of heat and solute result in morphological instability of the interface, forming different patterns of solidification structure and determining the mechanical properties of components. As the first observable phenomenon of the morphological instabilities, the planar inst...
2210.15123v2
2022-11-08
Thermally Induced Structural Evolution and Nanoscale Interfacial Dynamics in Layered Metal Chalcogenides
Layered chalcogenides including Bi2Te3, Sb2Te3, Bi-Sb-Te ternary alloys and heterostructures are known as great thermoelectric, topological insulators and recently highlighted as plasmonic building blocks beyond noble metals. Here, we conduct a joint in situ transmission electron microscopy (in situ TEM) and density fu...
2211.04018v2
2022-11-09
Linear complexions directly modify dislocation motion in face-centered cubic alloys
Linear complexions are defect phases that form in the presence of dislocations and thus are promising for the direct control of plasticity. In this study, atomistic simulations are used to model the effect of linear complexions on dislocation-based mechanisms for plasticity, demonstrating unique behaviors that differ f...
2211.04616v3
2022-11-10
Dynamic nanoindentation and short-range order in equiatomic NiCoCr medium entropy alloy lead to novel density wave ordering
Chemical short-range order (CSRO) is believed to be a key contributor to the exceptional properties of multicomponent alloys. However, direct validation and confirmation of CSRO has been highly elusive in most compounds. Recent studies for equiatomic NiCoCr alloys have shown that thermal treatments (i.e., annealing/agi...
2211.05436v1
2023-01-07
High-Entropy Hydrides for Fast and Reversible Hydrogen Storage at Room Temperature: Binding-Energy Engineering via First-Principles Calculations and Experiments
Despite high interest in compact and safe storage of hydrogen in the solid-state hydride form, the design of alloys that can reversibly and quickly store hydrogen at room temperature under pressures close to atmospheric pressure is a long-lasting challenge. In this study, first-principles calculations are combined with...
2301.02811v1
2023-02-03
Study of atomic disorder in Ni-V alloys
We present a pair distribution function (PDF) analysis from neutron diffraction data of the Ni$_{1-x}$V$_x$ alloy in the Ni-rich regime. Such structural study aims to clarify the origin of the magnetic inhomogeneities associated with the quantum Griffiths phase close to the ferromagnetic-paramagnetic quantum phase tran...
2302.01986v1
2023-02-09
A High-Throughput Computational Dataset of Halide Perovskite Alloys
Novel halide perovskites with improved stability and optoelectronic properties can be designed via composition engineering at cation and/or anion sites. Data-driven methods, especially high-throughput first principles computations and subsequent analysis based on unique materials descriptors, are key to achieving this ...
2302.04896v1
2023-02-13
Microstructural diversity, nucleation paths and phase behaviour in binary mixtures of charged colloidal spheres
We study low-salt, binary aqueous suspensions of charged colloidal spheres of size ratio Phi = 0.57, number densities below the eutectic number density n_E, and number fractions of p = 1.00-0.40. The typical phase obtained by solidification from a homogeneous shear-melt is a substitutional alloy of body centred cubic s...
2302.06382v1
2023-03-28
Impact of surface reflectivity on the ultra-fast laser melting of silicon-germanium alloys
Ultraviolet nanosecond laser annealing (LA) is a powerful tool where strongly confined heating and melting are desirable. In semiconductor technologies the importance of LA increases with the increasing complexity of the proposed integration schemes. Optimizing the LA process along with the experimental design is chall...
2303.15977v3
2023-04-08
Phase-field modeling of pitting and mechanically-assisted corrosion of Mg alloys for biomedical applications
A phase-field model is developed to simulate the corrosion of Mg alloys in body fluids. The model incorporates both Mg dissolution and the transport of Mg ions in solution, naturally predicting the transition from activation-controlled to diffusion-controlled bio-corrosion. In addition to uniform corrosion, the present...
2304.04762v2
2023-04-26
Giant segregation transition as origin of liquid metal embrittlement in the Fe-Zn system
A giant Zn segregation transition is revealed using CALPHAD-integrated density-based modelling of segregation into Fe grain boundaries (GBs). The results show that above a threshold of only a few atomic percent Zn in the alloy, a substantial amount of up to 60 at.\% Zn can segregate to the GB. We found that the amount ...
2304.13336v2
2023-05-09
Coexistence of multiple interfacial states at heterogeneous solid/liquid interface
The growing trend towards engineering interfacial complexion (or phase) transitions has been seen in the grain boundary and solid surface systems.Meanwhile, little attention has been paid to the chemically heterogeneous solid/liquid interfaces. In this work, novel in-plane multi-interfacial states coexist within the Cu...
2305.05488v1
2023-06-05
Verification of ultrafast spin transfer effects in FeNi alloys
The optical intersite spin transfer (OISTR) effect was recently verified in Fe$_{50}$Ni$_{50}$ using magneto-optical Kerr measurements in the extreme ultraviolet range. However, one of the main experimental signatures analyzed in this work, namely a magnetic moment increase at a specific energy in Ni, was subsequently ...
2306.02793v2
2023-06-09
Dangling bonds as possible contributors to charge noise in silicon and silicon-germanium quantum dot qubits
Spin qubits based on Si and Si$_{1-x}$Ge$_{x}$ quantum dot architectures exhibit among the best coherence times of competing quantum computing technologies, yet they still suffer from charge noise that limit their qubit gate fidelities. Identifying the origins of these charge fluctuations is therefore a critical step t...
2306.06229v1
2023-06-26
Multinary Alloying Suppresses Defect Formation in Emerging Inorganic Solar Cells
The Cu2ZnSn(S, Se)4 (CZTSSe) emerging inorganic solar cell is highly promising for accelerating the large-scale and low-cost applications of thin-film photovoltaics. It possesses distinct advantages such as abundant and non-toxic constituent elements, high material stability, and excellent compatibility with industrial...
2306.14629v1
2023-06-27
A Cluster-Based Computational Thermodynamics Framework with Intrinsic Chemical Short-Range Order: Part I. Configurational Contribution
Exploiting Chemical Short-Range Order (CSRO) is a promising avenue for manipulating the properties of alloys. However, existing modeling frameworks are not sufficient to predict CSRO in multicomponent alloys (>3 components) in an efficient and reliable manner. In this work, we developed a hybrid computational thermodyn...
2306.15384v2
2023-08-01
A novel method of experimental determination of grain stresses and critical resolved shear stresses for slip and twin systems in a magnesium alloy
A novel original method of determination of stresses and critical resolved shear stresses (CRSSs) using neutron diffraction was proposed. In this method, based on the crystallite group method, the lattice strains were measured in different directions and using different reflections hkl during uniaxial deformation of ma...
2308.00663v3
2023-08-06
Anatomy of spin Hall effect in ferromagnetic metals
The spin Hall effect in nonmagnetic materials has been intensively studied and became one of the most crucial spin-charge conversion mechanism in spintronics. However, the spin Hall effect in ferromagnetic metals has been less investigated and remains unclear. In this work, we investigate the spin Hall effect in repres...
2308.03111v1
2023-08-21
Thermoelectric properties and electronic structure of Cr(Mo,V)Nx thin films studied by synchrotron and lab-based X-ray spectroscopy
Chromium-based nitrides are used in hard, resilient coatings, and show promise for thermoelectric applications due to their combination of structural, thermal, and electronic properties. Here, we investigated the electronic structures and chemical bonding correlated to the thermoelectric properties of epitaxially grown...
2308.10750v2
2023-08-23
Atomic scale understanding of initial Cu-Ni oxidation from machine-learning accelerated first-principles simulations and in situ TEM experiments
The development of accurate methods for determining how alloy surfaces spontaneously restructure under reactive and corrosive environments is a key, long-standing, grand challenge in materials science. Current oxidation models, such as Cabrera-Mott, are based on macroscopic empirical knowledge that lacks fundamental in...
2308.11867v1
2023-09-02
An Isotropic Discretization with Semi-implicit Approach for Phase Field Model of Alloy Solidification
Quantitative phase field models have been extensively used to study the solidification behavior of alloys under different conditions. However, a longstanding challenge of phase field models is the directional bias caused by the discretization-induced lattice effects. In particular, widely used discretization methods ma...
2309.00836v1
2023-09-19
The GeSn Alloy and its Optoelectronic Properties: A Critical Review of the Current Understanding
GeSn is nowadays recognized as a promising candidate to enable monolithic on-chip Si photonics operating in the near-infrared (NIR) and short-wave infrared (SWIR) wavelengths. The addition of Sn to the Ge lattice induces a red-shift in the material bandgap, extending the absorption cut-off wavelength towards the infrar...
2309.10584v1
2023-09-24
Alloy Informatics through Ab Initio Charge Density Profiles: Case Study of Hydrogen Effects in Face-Centered Cubic Crystals
Materials design has traditionally evolved through trial-error approaches, mainly due to the non-local relationship between microstructures and properties such as strength and toughness. We propose 'alloy informatics' as a machine learning based prototype predictive approach for alloys and compounds, using electron cha...
2309.13673v1
2023-09-27
Electronic Properties of B$_x$Al$_{1-x}$N Computed from GW Simulations
Ultra-wide bandgap (UWBG) materials such as AlN and BN hold great promise for future power electronics due to their exceptional properties. They exhibit large band gaps, high breakdown fields, high thermal conductivity, and high mechanical strengths. AlN and BN have been extensively researched, however, their alloys, B...
2309.16050v2
2023-10-09
Modeling the effects of varying Ti concentration on the mechanical properties of Cu-Ti alloys
The mechanical properties of Cu-Ti alloys have been characterized extensively through experimental studies. However, a detailed understanding of why the strength of Cu increases after a small fraction of Ti atoms is added to the alloy is still missing. In this work, we address this question using density functional the...
2310.05415v1
2023-10-16
Computational design of optimal heterostructures for $β$-Ga$_2$O$_3$
Ga$_2$O$_3$ is a wide-bandgap material of interest for a wide variety of devices, many of these requiring heterostructures, for instance to achieve carrier confinement. A common method to create such heterostructures is to alloy with In$_2$O$_3$ or Al$_2$O$_3$. However, the lattice constants of these materials are sign...
2310.10557v2
2023-10-17
A method for crystallographic mapping of an alpha-beta titanium alloy with nanometre resolution using scanning precession electron diffraction and open-source software libraries
An approach for the crystallographic mapping of two-phase alloys on the nanoscale using a combination of scanned precession electron diffraction and open-source python libraries is introduced in this paper. This method is demonstrated using the example of a two-phase alpha / beta titanium alloy. The data was recorded u...
2310.11395v3
2023-11-24
Mechanism of charge transfer and electrostatic field fluctuations in high entropy metallic alloys
High entropy alloys present a new class of disordered metals which hold promising prospects for the next generation of materials and technology. However, much of the basic physics underlying these robust, multifunctional materials -- and those of other, more generic forms of disordered matter -- still remain the subjec...
2311.14463v1
2023-11-24
In situ Imaging of Precipitate Formation in Additively Manufactured Al-Alloys by Scanning X-ray Fluorescence
A new family of high-strength Al-alloys has recently been developed, tailored for the powder bed fusion-laser beam process. In these alloys, Mn, Cr and Zr are incorporated in solid solution at amounts up to three times that of equilibrium in the as-printed state. Mn and Cr-enriched precipitates that form during printin...
2311.14529v1
2023-11-28
Sluggish and Chemically-Biased Interstitial Diffusion in Concentrated Solid Solution Alloys: Mechanisms and Methods
Interstitial diffusion is a pivotal process that governs the phase stability and irradiation response of materials in non-equilibrium conditions. In this work, we study sluggish and chemically-biased interstitial diffusion in Fe-Ni concentrated solid solution alloys (CSAs) by combining machine learning (ML) and kinetic...
2311.16727v1
2023-11-28
Local distortions of the crystal structure and their influence on the electronic structure and superconductivity of the high-entropy alloy (TaNb)0.67(HfZrTi)0.33
Local distortions of the crystal structure and their influence on the electronic structure, electron-phonon interaction, and superconductivity are theoretically studied in the superconducting high-entropy alloy (HEA) (TaNb)$_{0.67}$(HfZrTi)$_{0.33}$. Distortions of the crystal lattice are caused by the relaxation of at...
2311.16767v2
2024-01-11
Accelerated Development of Multicomponent Alloys in Discrete Design Space Using Bayesian Multi-Objective Optimisation
Bayesian optimisation (BO) protocol based on Active Learning (AL) principles has garnered significant attention due to its ability to efficiently optimise black-box objective functions. This capability is a prerequisite for guiding autonomous and high-throughput materials design and discovery processes. However, its ap...
2401.06106v1
2024-01-19
An Experimental Estimation Method of Diffusion Coefficients in Ternary and Multicomponent Systems from a Single Diffusion Couple Profile
Until recently, it was textbook knowledge that the diffusion coefficients could not be estimated in a multi-component system following the widely practised diffusion couple method. The recently proposed constrained diffusion couple methods need two intersecting diffusion paths in a multi-component space with very well-...
2401.10684v1
2024-01-25
Effects of Chemical Short Range Order on Percolation in Binary Alloys
We develop a percolation model for face centered cubic binary alloys with chemical short-range order (SRO) to account for chemical ordering/clustering that occurs in nominally random solid solutions. We employ a Monte Carlo lattice generation scheme that directly utilizes the first nearest neighbor Warren-Cowley SRO pa...
2401.13954v1
2024-01-30
Effect of the growth temperature and the AlN mole fraction on In incorporation and properties of quaternary III-nitride layers grown by molecular beam epitaxy
Indium incorporation into wurtzite (0001)-oriented In$_{x}$Al$_{y}$Ga$_{1-x-y}$N layers grown by plasma-assisted molecular beam epitaxy was studied as a function of the growth temperature (565-635 $^{\circ}$C) and the AlN mole fraction (0.01 < y < 0.27). The layer stoichiometry was determined by Rutherford backscatteri...
2402.00581v1
2024-02-13
Machine Learning Potential Powered Insights into the Mechanical Stability of Amorphous Li-Si Alloys
Understanding the mechanical properties of solid-state materials at the atomic scale is crucial for developing novel materials. For example, amorphous LiSi alloys are attractive anode materials for solid-state Li-ion batteries but face mechanical instabilities due to significant volume variations with changing Li conte...
2402.08834v1
2024-02-29
A-15 type superconducting hydride $La_4H_{23}$: Nanograined structure with low strain, strong electron-phonon interaction, and moderate level of nonadiabaticity
For seven decades by A-15 superconductors we meant metallic $A_3B$ alloys (where A is a transition metal, and B is groups IIIB and IVB element) discovered by Hardy and Hulm (Phys. Rev. 89, 884 (1953)). Nb3Ge exhibited the highest superconducting transition temperature, $T_c = 23 K$, among these alloys. One of these all...
2402.19384v3
2024-03-04
Interplay between alloying and tramp element effects on temper embrittlement in bcc iron: DFT and thermodynamic insights
The details of the temper embrittlement mechanism in steels caused by impurities are unknown. Especially from an atomistic point of view, there are still open questions regarding their interactions with alloying elements such as Ni, Cr, and Mo. Therefore, we used density functional theory to investigate the segregation...
2403.02186v1
2024-03-22
Efficient first principles based modeling via machine learning: from simple representations to high entropy materials
High-entropy materials (HEMs) have recently emerged as a significant category of materials, offering highly tunable properties. However, the scarcity of HEM data in existing density functional theory (DFT) databases, primarily due to computational expense, hinders the development of effective modeling strategies for co...
2403.15579v1
2024-04-01
Electronic structure and thermoelectric properties of epitaxial Sc1-xVxNy thin films grown on MgO(001)
The electronic structure of Sc1-xVxNy epitaxial films with different alloying concentrations of V are investigated with respect to effects on thermoelectric properties. Band structure calculations on Sc0.75V0.25N indicate that V 3d states lie in the band gap of the parent ScN compound in the vicinity of the Fermi level...
2404.01417v1
2024-04-12
Lowering the Exponential Wall: Accelerating High-Entropy Alloy Catalysts Screening using Local Surface Energy Descriptors from Neural Network Potentials
Computational screening is indispensable for the efficient design of high-entropy alloys (HEAs), which hold great potential for catalytic applications. However, the chemical space of HEAs is exponentially vast with respect to the number of constituent elements, and even screening calculations using machine learning pot...
2404.08413v1
2024-04-15
Martensite decomposition kinetics in additively manufactured Ti-6Al-4V alloy: in-situ characterisation and phase-field modelling
Additive manufacturing of Ti-6Al-4V alloy via laser powder-bed fusion leads to non-equilibrium $\alpha'$ martensitic microstructures, with high strength but poor ductility and toughness. These properties may be modified by heat treatments, whereby the $\alpha'$ phase decomposes into equilibrium $\alpha+\beta$ structure...
2404.09806v1
1995-02-24
Model for the thermal conductivity of a quasicrystalline alloy
We present a simple model for the observed temperature dependence of the thermal conductivity of AlPdMn (Chernikov et al, Phys.Rev.B vol.51, (1995),153). We account for the low temperature data, upto and including the plateau of the thermal conductivity, and discuss the similarities and the differences between the quas...
9502105v1
1997-01-20
Kondo Effect in a Metal with Correlated Conduction Electrons
The large-degeneracy expansion for dilute magnetic alloys is extended to account for conduction electrons interactions. Particular attention is paid to the renormalization of the hybridization vertex which affects the low-energy excitations. As a first example, we calculate the enhanced characteristic energy $k_BT_0$ i...
9701137v1
1997-06-24
An Extended Anderson Model that shows Decreasing Resistivity with Decreasing Temperature
The resistivity for an extended two channel Anderson model is calculated. When the temperature decreases, it decreases logarithmically, and has T^1/2 anomaly at very low temperatures, as seen in some dilute U alloys. The single-particle and the spin excitation spectra are also calculated.
9706241v1
1999-08-10
Critical adsorption near edges
Symmetry breaking surface fields give rise to nontrivial and long-ranged order parameter profiles for critical systems such as fluids, alloys or magnets confined to wedges. We discuss the properties of the corresponding universal scaling functions of the order parameter profile and the two-point correlation function an...
9908155v1
2000-05-24
First order transition from ferro- to antiferromagnetism in CeFe$_2$ based pseudobinary alloys
We present results of ac susceptibility measurements highlighting the presence of thermal hysteresis and phase coexistence across the ferro-to antiferromagnetic transition in various CeFe$_2$ based pseudobinary systems. These results indicate that the ferro-to antiferromagnetic transition in these systems is first orde...
0005399v1
2001-01-25
Specific heat of a Fermi system near ferromagnetic quantum phase transition
We calculate the specific heat for an interacting Fermi system near the ferromagnetic phase transition using the Renormalization Group method. The temperature dependence of the specific heat present for dimension D=3 a logarithmic dependence which shows that the fermionic excitations reaches a non - Fermi behavior. The...
0101392v1
2003-11-06
Alloy effects in GaInN/GaN heterostructures
We show that the large band offsets between GaN and InN and the heavy carrier effective masses preclude the use of the Virtual Crystal Approximation to describe the electronic structure of Ga_(1-x)In_(x)N/GaN heterostructures while this approximation works very well for the Ga_(1-x)In_(x)As/GaAs heterostructures.
0311133v1
2004-06-11
Disorder- and correlation-driven metal-insulator transitions
Metal-insulator transitions driven by disorder (Delta) and/or by electron correlations (U) are investigated within the Anderson-Hubbard model with local binary-alloy disorder using a simple but consistent mean-field approach. The Delta-U phase diagram is derived and discussed for T=0 and finite temperatures.
0406266v2
2004-07-26
Magnetic transition in Ni-Pt alloy Systems : Experiment and Theory
We report here the preparation and measurements on the susceptibility, sound velocity and internal friction for Ni-Pt systems. We then compare these experimental results with the first principle theoretical predictions and show that there is reasonable agreement with experiment and theory.
0407661v1