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2016-05-13
Quantifying structure-property relationships during resistance spot welding of an aluminum 6061-T6 joint
Microstructure-property relationships of resistance spot welded 6061-T6 aluminum alloy lap joints were investigated via mechanical testing and microscopy techniques. Quasi-static tensile and novel shear punch tests were employed to measure the mechanical properties of the distinct weld regions. Quasi-static tensile and...
1605.04251v1
2016-05-14
Observation of orbital two-channel Kondo effect in a ferromagnetic L10-MnGa film
The experimental existence and stability of the quantum criticality point of the two-channel Kondo (2CK) effect displaying exotic non-Fermi liquid physics has been buried in persistent confusion despite the intensive theoretical and experimental efforts in past three decades. Here we report an experimental realization ...
1605.04366v4
2016-05-17
Pressure-Driven Quantum Criticality and T/H Scaling in the Icosahedral Au-Al-Yb Approximant
We report on ac magnetic susceptibility measurements under pressure of the Au-Al-Yb alloy, a crystalline approximant to the icosahedral quasicrystal that shows unconventional quantum criticality. In describing the susceptibility as $\chi(T)^{-1} - \chi(0)^{-1} \propto T^{\gamma}$, we find that $\chi(0)^{-1}$ decreases ...
1605.05012v1
2016-05-25
Quantum Criticality and Inhomogeneous Magnetic Order in Fe-doped alpha-YbAlB4
The intermediate-valent polymorphs $\alpha$- and $\beta$-YbAlB$_4$ exhibit quantum criticality and other novel properties not usually associated with intermediate valence. Iron doping induces quantum criticality in $\alpha$-YbAlB$_4$ and magnetic order in both compounds. We report results of muon spin relaxation ($\mu$...
1605.07993v1
2016-05-31
Spin-Orbit Torques in ferrimagnetic GdFeCo Alloys
The spin-orbit torque switching of ferrimagnetic Gd$_x$(Fe$_{90}$Co$_{10}$)$_{100-x}$ films was studied for both transition metal (TM)-rich and rare earth (RE)-rich configurations. The spin-orbit torque driven magnetization switching follows the same handedness in TM-rich and RE-rich samples with respect to the total m...
1605.09498v1
2016-06-05
A bound on the averaged spectral shift function and a lower bound on the density of states for random Schrödinger operators on $\mathbb{R}^d$
We obtain a bound on the expectation of the spectral shift function for alloy-type random Schr\"odinger operators on $\mathbb{R}^d$ in the region of localisation, corresponding to a change from Dirichlet to Neumann boundary conditions along the boundary of a finite volume. The bound scales with the area of the surface ...
1606.01579v1
2016-06-07
Characterization of crystal structure and precipitation crystallography of a new MgxAl2-xGd phase in Mg97Al1Gd2 alloy
The composition, crystal structure and precipitation crystallography of a newly found precipitate are characterized by a Cs-corrected scanning transmission electron microscopy (STEM). The composition of the plate-like precipitate could be expressed as MgxAl2-xGd (x = 0.38), and its crystal structure is the same as the ...
1606.02067v1
2016-06-08
Skyrmions with attractive interactions in an ultrathin magnetic film
We determined the parameters of a classical spin Hamiltonian describing an Fe monolayer on Pd(111) surface with a Pt_{1-x}Ir_{x} alloy overlayer from ab initio calculations. While the ground state of the system is ferromagnetic for x=0.00, it becomes a spin spiral state as Ir is intermixed into the overlayer. Although ...
1606.02464v2
2016-06-17
Ultra-high oxidation potential of Ti/Cu-SnO2 anodes fabricated by spray pyrolysis for wastewater treatment
High oxidation potential indicates anodes have high oxidation power and high current efficiency for organics oxidation. In this paper, we prepared Ti/Cu-SnO2 anodes using spray pyrolysis method. The Ti/Cu-SnO2 anodes have an ultra-high oxidation potential of about 2.7 V vs NHE, suitable for use in wastewater treatment....
1606.06332v1
2016-06-17
Effects of nickel doping on the preferred orientation and oxidation potential of Ti/Sb-SnO2 anodes prepared by spray pyrolysis
Nickel and antimony co-doped Ti/SnO2 (Ti/Ni-Sb-SnO2) anodes were prepared by spray pyrolysis. Effects of nickel concentration on the structure and onset potential for oxygen evolution of Ti/Ni-Sb-SnO2 anodes have been systematically investigated. XRD analyses suggest that SnO2 thin films grow in preferential orientatio...
1606.06574v1
2016-07-01
Saturation magnetization and band gap tuning in BiFeO$_3$ nanoparticles via co-substitution of Gd and Mn
In this investigation, Gd and Mn co-doped Bi$_{0.85}$Gd$_{0.15}$Fe$_{1-x}$Mn$_x$O$_3$ (x=0.0-0.15) nanoparticles have been prepared to report the influence of co-substitution on their structural, optical, magnetic and electrical properties. Due to simultaneous substitution of Gd and Mn in BiFeO$_3$, the crystal structu...
1607.00158v1
2016-07-07
Giant perpendicular magnetic anisotropy energies in CoPt thin films: Impact of reduced dimensionality and imperfections
The impact of reduced dimensionality on the magnetic properties of the tetragonal L1$_{0}$ CoPt alloy is investigated from ab-initio considering several kinds of surface defects. By exploring the dependence of the magnetocrystalline anisotropy energy (MAE) on the thickness of CoPt thin films, we demonstrate the crucial...
1607.01919v2
2016-07-18
Engineering the polar magneto-optical Kerr effect in strongly strained L10-MnAl films
We report the engineering of the polar magnetooptical (MO) Kerr effect in perpendicularly magnetized L10-MnAl epitaxial films with remarkably tuned magnetization, strain, and structural disorder by varying substrate temperature (Ts) during molecular-beam epitaxy growth. The Kerr rotation was enhanced by a factor of up ...
1607.04938v4
2016-07-21
Phonon broadening from supercell lattice dynamics: random and correlated disorder
We demonstrate how supercell implementations of conventional lattice dynamical calculations can be used to determine the extent and nature of disorder-induced broadening in the phonon dispersion spectrum of disordered crystalline materials. The approach taken relies on band unfolding, and is first benchmarked against v...
1607.06337v1
2016-07-22
Wavelength extension beyond 1.5 micrometer in symmetric InAs quantum dots on InP(111)A using droplet epitaxy
By using a C3v symmetric (111) surface as a growth substrate, we are able to achieve high structural symmetry in self-assembled quantum dots, which are suitable for use as quantum-entangled photon emitters. Here we report on the wavelength controllability of InAs dots on InP(111)A, which we realized by tuning the terna...
1607.06859v1
2016-07-27
Influence of complex disorder on skew-scattering Hall effects in $L1_0$-ordered FePt alloy
We show by first-principles calculations that the skew-scattering anomalous Hall and spin-Hall angles of L$1_0$-ordered FePt drastically depend on different types of disorder. A different sign of the AHE is obtained when slightly deviating from the stoichiometric ratio towards the Fe-rich side as compared to the Pt-ric...
1607.08042v1
2016-08-05
Mechanical dissipation in MoRe superconducting metal drums
We experimentally investigate dissipation in mechanical resonators made of a disordered superconducting thin film of Molybdenum-Rhenium(MoRe) alloy. By electrostatically driving the drum with a resonant AC voltage, we detect its motion using a superconducting microwave cavity. From the temperature dependence of mechani...
1608.01871v1
2016-08-08
Computational study of atomic mobility in HCP Mg-Al-Zn ternary alloys
The experimental data in the literature for the hcp phase of the Mg-Al-Zn ternary system have been critically reviewed. Based on the concentration profiles from the literature, the diffusion coefficients have been re-extracted using the Hall method for the impurity diffusion, and the Sauer-Freise and the Whittle-Green ...
1608.02349v1
2016-08-18
Driving force for martensitic transformation in Ni$_{2}$Mn$_{1+x}$Sn$_{1-x}$
The martensitic transformation in Ni$_{2}$Mn$_{1+x}$Sn$_{1-x}$ alloys has been investigated within ab-initio density functional theory. The experimental trend of a martensitic transition happening beyond $x$ = 0.36 is captured within these calculations. The microscopic considerations leading to this are traced to incre...
1608.05181v1
2016-08-24
AlGaN Channel Field Effect Transistors with Graded Heterostructure Ohmic Contacts
We report on ultra-wide bandgap (UWBG) Al0.75Ga0.25N channel metal-insulator-semiconductor field-effect transistors (MISFET) with heterostructure engineered low-resistance ohmic contacts. The low intrinsic electron affinity of AlN (0.6 eV) leads to large Schottky barriers at metal-AlGaN interface, resulting in highly r...
1608.06686v1
2016-08-24
Chemical ordering beyond the superstructure in long-range ordered systems
To describe chemical ordering in solid solutions systems Warren-Cowley short-range parameters are ordinarily used. However, they are not directly suited for application to long-range ordered systems, as they do not converge to zero for large separations. It is the aim of this paper to generalize the theory to long-rang...
1608.06870v1
2016-09-02
Temperature-dependent photoluminescence characteristics of GeSn epitaxial layers
GeSn epitaxial heterostructures are emerging as prominent candidates for the monolithic integration of light sources on Si substrates. Here we propose a judicious explanation for their temperature-dependent photoluminescence (PL) that is based upon the so far disregarded optical activity of dislocations. By working at ...
1609.00542v1
2016-09-05
Critical Current Oscillations of Josephson Junctions Containing PdFe Nanomagnets
Josephson junctions with ferromagnetic layers are vital elements in a new class of cryogenic memory devices. One style of memory device contains a spin valve with one "hard" magnetic layer and one "soft" layer. To achieve low switching fields, it is advantageous for the soft layer to have low magnetization and low magn...
1609.01330v1
2016-09-06
Impact of finite temperatures on the transport properties of Gd from first principles
Finite temperature effects have a pronounced impact on the transport properties of solids. In magnetic systems, besides the scattering of conduction electrons by impurities and phonons, an additional scattering source coming from the magnetic degrees of freedom must be taken into account. A first-principle scheme which...
1609.01767v1
2016-09-13
Extension of Configurational Polyhedra to Finite Temperature Property
Configurational polyhedora (CP) is a hyperpolyhedra on multidimensional configuration space, whose vertex (and edges) corresponds to upper or lower limit value of correlation functions for all possible atomic configuration on given lattice. In classical systems where physical property including internal energy and elas...
1609.03859v1
2016-09-14
Magnetic field effects in electron systems with imperfect nesting
We analyze the effects of an applied magnetic field on the phase diagram of a weakly-correlated electron system with imperfect nesting. The Hamiltonian under study describes two bands: electron and hole ones. Both bands have spherical Fermi surfaces, whose radii are slightly mismatched due to doping. These types of mod...
1609.04279v2
2016-09-19
Switching ferromagnetic spins by an ultrafast laser pulse: Emergence of giant optical spin-orbit torque
Faster magnetic recording technology is indispensable to massive data storage and big data sciences. {All-optical spin switching offers a possible solution}, but at present it is limited to a handful of expensive and complex rare-earth ferrimagnets. The spin switching in more abundant ferromagnets may significantly exp...
1609.05855v1
2016-09-26
Far-infrared quantum cascade lasers operating in AlAs phonon Reststrahlen band
We report on the operation of a double metal waveguide far-infrared quantum cascade laser emitting at 28 $\mu$m, corresponding to the AlAs-like phonon Reststrahlen band. To avoid absorption by AlAs-like optical phonons, the Al-free group-V alloy GaAs$_{0.51}$Sb$_{0.49}$ is used as a barrier layer in the bound-to-contin...
1609.08196v1
2016-09-28
ThCr2Si2-type Ru-based superconductors LaRu2M2 (M = P and As): An ab-initio investigation
ThCr2Si2-type Ru-based superconductors LaRu2P2 and LaRu2As2 with Tc ~ 4 K and 7.8 K respectively have been reported very recently. Using the first principles method we investigate the details physical and superconducting properties including the structural properties, electronic properties, elastic properties and Therm...
1609.08856v2
2016-09-29
Raman study of the vibrational modes in ZnGeN2 (0001)
A Raman spectroscopy study was carried out for ZnGeN2 with direction of propagation along the (0001) crystallographic direction on hexagonal single crystal platelets obtained by reaction of gaseous ammonia with a Zn-Ge-Sn liquid alloy at 758 degree C. The sample geometry allowed measurement of the a2 and a1 Raman modes...
1609.09535v1
2016-10-04
Reasoning about identifier spaces: How to make Chord correct
The Chord distributed hash table (DHT) is well-known and often used to implement peer-to-peer systems. Chord peers find other peers, and access their data, through a ring-shaped pointer structure in a large identifier space. Despite claims of proven correctness, i.e., eventual reachability, previous work has shown that...
1610.01140v2
2016-10-06
The molybdenum-titanium phase diagram evaluated from ab-initio calculations
The design of next generation \beta-type titanium implants requires detailed knowledge of the relevant stable and metastable phases at temperatures where metallurgical heat treatments can be performed. Recently, a standard specification for surgical implant applications was established for Mo-Ti alloys. However, the th...
1610.01995v1
2016-10-10
Origin of magnetic anisotropy in doped Ce$_2$Co$_{17}$ alloys
Magnetocrystalline anisotropy (MCA) in doped Ce$_{2}$Co$_{17}$ and other competing structures was investigated using density functional theory. We confirmed that the MCA contribution from dumbbell Co sites is very negative. Replacing Co dumbbell atoms with a pair of Fe or Mn atoms greatly enhance the uniaxial anisotrop...
1610.02767v2
2016-10-11
Large magnetic anisotropy predicted for rare-earth free Fe16-xCoxN2 alloys
Structures and magnetic properties of Fe16-xCoxN2 are studied using adaptive genetic algorithm and first-principles calculations. We show that substituting Fe by Co in Fe16N2 with Co/Fe ratio smaller than 1 can greatly improve the magnetic anisotropy of the material. The magnetocrystalline anisotropy energy from first-...
1610.03544v1
2016-10-12
On the limits to mobility in InAs quantum wells with nearly lattice-matched barriers
The growth and the density dependence of the low temperature mobility of a series of two-dimensional electron systems confined to un-intentionally doped, low extended defect density InAs quantum wells with Al$_{1-x}$Ga$_{x}$Sb barriers are reported. The electron mobility limiting scattering mechanisms were determined b...
1610.03785v2
2016-10-16
Chalcogenide Perovskites- an Emerging Class of Ionic Semiconductors
We report the synthesis and characterization of a novel class of ionic semiconductor materials- inorganic chalcogenide perovskites. Several different compounds including BaZrS3, CaZrS3, SrTiS3 and SrZrS3 were synthesized by high temperature sulfurization of their oxide counterparts. Their crystal structures were identi...
1610.04882v1
2016-10-17
Modified Bohm's theory for abstruse measurements: application to layer depth profiling by Auger spectroscopy
Modified Bohm formalism is applied to solve a problem of abstruse layer depth profiles measured by the Auger electron spectroscopy technique in real physical systems, i.e., the desorbed carbon/passive layer on NiTi substrate and the adsorbed oxygen/surface of NiTi alloy. It is shown that abstruse layer profiles may be ...
1610.05100v2
2016-10-29
Excess Volume at Grain Boundaries in hcp Metals
The excess volume associated with grain boundaries represents a key structural parameter for the characterization of grain boundaries. It plays a critical role in segregation of impurity and alloy elements to grain boundaries, and influences significantly the mechanical and functional properties of materials. We have c...
1610.09494v2
2016-10-30
Insulator-metal transition in deep Sr-vacant spin-orbit Mott insulator Sr2IrO4
Sr2IrO4 exhibits a novel insulating state assisted by spin-orbit interactions. A series of polycrystalline samples of Sr2-xIrO4 have been synthesized. It is found that deep Sr-vacancies of Sr2-xIrO4 greatly reduce the rotation of IrO6 octahedral, and more importantly, a significant structural change occurs around x = 0...
1610.09594v1
2016-10-31
Compositional asymmetry of disordered structure: Role of spatial constraint
When spatial constraint for the constituents (e.g., atom or particle) of system is once given, disordered structure for non-interacting system in equilibrium states is symmetric with respect to equiatomic composition. Meanwhile, when the interaction between constituents is introduced, this symmetry is typically broken,...
1610.09797v2
2016-11-01
Shear softening of Earth's inner core indicated by its high Poisson's ratio and elastic anisotropy
Earth's inner core exhibits an unusually high Poisson's ratio and noticeable elastic anisotropy. The mechanisms responsible for these features are critical for understanding the evolution of the Earth but remain unclear. This study indicates that once the correct formula for the shear modulus is used, shear softening c...
1611.00244v1
2016-11-14
Local environment effects on a charge carrier injected into an Ising chain
We present numerically exact results for the spectral function of a single charge carrier that is injected into an Ising chain at finite temperature $T$. Both ferromagnetic and antiferromagnetic coupling between the Ising spins are considered. The interaction between the carrier and the Ising spins is assumed to be on-...
1611.04560v1
2016-11-22
AlM2B2 (M=Cr, Mn, Fe, Co, Ni): a group of nanolaminated materials
Combining theory with experiments, we study the phase stability, elastic properties, electronic structure and hardness of layered ternary borides AlCr2B2, AlMn2B2, AlFe2B2, AlCo2B2, and AlNi2B2. We find that the first three borides of this series are stable phases, while AlCo2B2 and AlNi2B2 are metastable. We show that...
1611.07190v1
2016-11-24
Argon assisted chemical vapor deposition of CrO$_2$: an efficient process leading to high quality epitaxial films
A comparative study of the structural, microstructural and magnetic properties of CrO$_2$ thin films grown onto (110) and (100) TiO$_2$ rutile single crystal substrates by chemical vapor deposition (CVD), using CrO$_3$ as chromium precursor and either oxygen or argon as carrier gas is presented. Our results show that g...
1611.08155v1
2016-11-24
Linking microstructural evolution and macro-scale friction behavior in metals
A correlation is established between the macro-scale friction regimes of metals and a transition between two dominant atomistic mechanisms of deformation. Metals tend to exhibit bi-stable friction behavior -- low and converging or high and diverging. These general trends in behavior are shown to be largely explained us...
1611.08200v1
2016-11-28
Magnetism of a sigma-phase Fe60V40 alloy: magnetic susceptibilities and magnetocaloric effect studies
Magnetic properties of a sigma-phase Fe60V40 intermetallic compound were studied by means of ac and dc magnetic susceptibility and magnetocaloric effect measurements. The compound is a soft magnet yet it was found to behave like a re-entrant spin-glass system. The magnetic ordering temperature was found to be T_C ca.17...
1611.09186v1
2017-01-06
Investigation of periodic-layered structure in Zn/CuxTiy systems
Diffusion couples Zn/CuxTiy were prepared by the melting contact method and then annealed at 663K for various times. Using scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), we discovered 7 new systems, i.e. Zn/Cu9Ti, Zn/Cu4Ti, Zn/Cu2Ti, Zn/Cu7Ti3, Zn/Cu3Ti2, Zn/Cu11Ti9 and Zn/Cu9Ti11, ...
1701.01594v1
2017-01-09
Generating derivative superstructures for systems with high configurational freedom
Modeling potential alloys requires the exploration of all possible configurations of atoms. Additionally, modeling the thermal properties of materials requires knowledge of the possible ways of displacing the atoms. One solution to finding all symmetrically unique configurations and displacements is to generate the com...
1701.02382v1
2017-01-11
Potassium self-diffusion in a K-rich single-crystal alkali feldspar
The paper reports potassium diffusion measurements performed on gem-quality single-crystal alkali feldspar in the temperature range from $1169$ to $1021 \, \mbox{K}$. Natural sanidine from Volkesfeld, Germany was implanted with $\mbox{}^{43}\mbox{K}$ at the ISOLDE/CERN radioactive ion-beam facility normal to the (001) ...
1701.02884v1
2017-01-11
Interface mediated mechanisms of plastic strain recovery in AgCu alloy
Through the combination of transmission electron microscopy analysis of the deformed microstructure and molecular dynamics computer simulations of the deformation processes, the mechanisms of plastic strain recovery in bulk AgCu eutectic with either incoherent twin or cube-on-cube interfaces between the Ag and Cu layer...
1701.03033v1
2017-01-13
Raman spectral shift versus strain and composition in GeSn layers with: 6 to 15% Sn contents
GeSn alloys are the subject of intense research activities as these group IV semiconductors present direct bandgap behaviors for high Sn contents. Today, the control of strain becomes an important challenge to improve GeSn devices. Strain micro-measurements are usually performed by Raman spectroscopy. However, differen...
1701.03788v1
2017-01-16
The role of atomic orbitals of doped earth-abundant metals on designed copper catalytic surfaces
It is a general challenge to design highly active or selective earth-abundant metals for catalytic hydrogenation. Here, we demonstrated an effective computational approach based on inverse molecular design theory to deterministically search for optimal binding sites on Cu (100) surface through the doping of Fe and/or Z...
1701.04333v2
2017-01-23
Arbitrary order 2D virtual elements for polygonal meshes: Part II, inelastic problem
The present paper is the second part of a twofold work, whose first part is reported in [3], concerning a newly developed Virtual Element Method (VEM) for 2D continuum problems. The first part of the work proposed a study for linear elastic problem. The aim of this part is to explore the features of the VEM formulation...
1701.06676v2
2017-01-24
Ion-Beam-Induced Defects in CMOS Technology: Methods of Study
Ion implantation is a non-equilibrium doping technique which introduces impurity atoms into a solid regardless of thermodynamic considerations. The formation of metastable alloys above the solubility limit, minimized contribution of lateral diffusion processes in device fabrication, and possibility to reach high concen...
1701.07087v2
2017-01-25
Direct Mapping of Spin and Orbital Entangled Wavefunction under Interband Spin-Orbit coupling of Rashba Spin-Split Surface States
We use spin- and angle-resolved photoemission spectroscopy (SARPES) combined with polarization-variable laser and investigate the spin-orbit coupling effect under interband hybridization of Rashba spin-split states for the surface alloys Bi/Ag(111) and Bi/Cu(111). In addition to the conventional band mapping of photoem...
1701.07269v1
2017-01-25
Thin films with precisely engineered nanostructures
Synthesis of rationally designed nanostructured materials with optimized mechanical properties, e.g., high strength with considerable ductility, requires rigorous control of diverse microstructural parameters including the mean size, size dispersion and spatial distribution of grains. However, currently available synth...
1701.07509v1
2017-01-30
Does the repulsive interatomic potential determine fragility in metallic liquids?
The dynamical behavior of liquids is frequently characterized by the fragility, which can be defined from the temperature dependence of the shear viscosity, {\eta}. For a strong liquid, the activation energy for {\eta} changes little with cooling towards the glass transition temperature, Tg. The change is much greater ...
1701.08454v1
2017-03-01
Tunnel-injected sub-260 nm ultraviolet light emitting diodes
We report on tunnel-injected deep ultraviolet light emitting diodes (UV LEDs) configured with a polarization engineered Al0.75Ga0.25N/ In0.2Ga0.8N tunnel junction structure. Tunnel-injected UV LED structure enables n-type contacts for both bottom and top contact layers. However, achieving Ohmic contact to wide bandgap ...
1703.00117v1
2017-03-01
Thickness Dependence of Spin-Orbit Torques in Ferrimagnetic GdFeCo Alloys
So far, studies of spin-orbit torques (SOT) in ferromagnets with perpendicular magnetic anisotropy (PMA) have been restricted to ultra thin samples, while a systematic study of its thickness dependence is still lacking in literature. In this article we discuss the thickness dependence of SOT in GdFeCo samples with bulk...
1703.00146v1
2017-03-12
Standardization of Proton Induced X-Ray Emission for Analysis of Trace Elements in Thick Targets
This paper presents the standardization of Proton Induced X-rays Emission (PIXE) technique for the trace element analysis of thick standard samples. Three standard reference materials (SRMs) viz-\`a-vis titanium, copper and iron base alloys were used for the study due to their availability. The protons beam was acceler...
1703.04532v2
2017-03-20
Elastic, thermodynamic, electronic and optical properties of recently discovered transition metal boride NbRuB superconductors: an ab-initio investigation
The elastic, thermodynamic, electronic, and optical properties of recently discovered and potentially technologically important transition metal boride NbRuB, have been investigated using the density functional formalism. Both generalized gradient approximation (GGA) and local density approximation (LDA) were used for ...
1703.06707v1
2017-03-24
Studies of the Response of the SiD Silicon-Tungsten ECal
Studies of the response of the SiD silicon-tungsten electromagnetic calorimeter (ECal) are presented. Layers of highly granular (13 mm^2 pixels) silicon detectors embedded in thin gaps (~ 1 mm) between tungsten alloy plates give the SiD ECal the ability to separate electromagnetic showers in a crowded environment. A ni...
1703.08605v1
2017-03-31
Chalcogenide hyperbolic metamaterial with switchable negative refraction
Chalcogenide glasses are exceptional materials that show a wide contrast in optical properties upon phase change and are highly researched for reconfigurable electronic and nanophotonic devices. Here, we report the first proof-of-concept demonstration of a non-volatile, switchable hyperbolic metamaterial based on a cha...
1703.10753v1
2017-07-11
Aging, memory, and nonhierarchical energy landscape of spin jam
The notion of complex energy landscape underpins the intriguing dynamical behaviors in many complex systems ranging from polymers, to brain activity, to social networks and glass transitions. The spin glass state found in dilute magnetic alloys has been an exceptionally convenient laboratory frame for studying complex ...
1707.03086v1
2017-07-13
Towards the ab initio based theory of the phase transformations in iron and steel
Despite of the appearance of numerous new materials, the iron based alloys and steels continue to play an essential role in modern technology. The properties of a steel are determined by its structural state (ferrite, cementite, pearlite, bainite, martensite, and their combination) that is formed under thermal treatmen...
1707.04287v1
2017-07-13
Brittle to Quasi-Brittle Transition and Crack Initiation Precursors in Disordered Crystals
Crack initiation emerges due to a combination of elasticity, plasticity, and disorder, and it is heavily dependent on the material's microstructural details. In this paper, we investigate brittle metals with coarse-grained, microstructural disorder that could originate in a material's manufacturing process, such as all...
1707.04332v1
2017-07-17
Natural selection as coarsening
Analogies between evolutionary dynamics and statistical mechanics, such as Fisher's second-law-like "fundamental theorem of natural selection" and Wright's "fitness landscapes", have had a deep and fruitful influence on the development of evolutionary theory. Here I discuss a new conceptual link between evolution and s...
1707.05317v2
2017-07-18
Crystal Growth in Fluid Flow: Nonlinear Response Effects
We investigate crystal-growth kinetics in the presence of strong shear flow in the liquid, using molecular-dynamics simulations of a binary-alloy model. Close to the equilibrium melting point, shear flow always suppresses the growth of the crystal-liquid interface. For lower temperatures, we find that the growth veloci...
1707.05513v1
2017-07-18
From anti-perovskite to double anti-perovskite: lattice chemistry basis for super-fast transportation of Li+ ions in cubic solid lithium halogen-chalcogenides
Using a materials genome approach on the basis of the density functional theory, we have formulated a new class of inorganic electrolytes for fast diffusion of Li+ ions, through fine-tuning of lattice chemistry of anti-perovskite structures. Systematic modelling has been carried out to elaborate the structural stabilit...
1707.05868v1
2017-07-27
Nominal vs. actual supersaturation of solutions
Following the formalism of the Classical Nucleation Theory beyond the dilute solution approximation, this paper considers a difference between the actual solute supersaturation (given by the present-to-saturated solute activity ratio) and the nominal supersaturation (given by the present-to-saturated solute concentrati...
1707.08777v3
2017-07-27
Design rules for modulation-doped AlAs quantum wells
Thanks to their multi-valley, anisotropic, energy band structure, two-dimensional electron systems (2DESs) in modulation-doped AlAs quantum wells (QWs) provide a unique platform to investigate electron interaction physics and ballistic transport. Indeed, a plethora of phenomena unseen in other 2DESs have been observed ...
1707.09011v2
2017-08-02
Realistic finite temperature simulations of magnetic systems using quantum statistics
We have performed realistic atomistic simulations at finite temperatures using Monte Carlo and atomistic spin dynamics simulations incorporating quantum (Bose-Einstein) statistics. The description is much improved at low temperatures compared to classical (Boltzmann) statistics normally used in these kind of simulation...
1708.00709v1
2017-08-03
Ordered FePdCu nanoisland arrays made by templated solid-state dewetting
Ordered FePdCu nanoisland arrays were formed by annealing at 600oC, which caused solid state dewetting of [Cu/Fe/Pd] multilayers deposited on self-assembled SiO2 nanospheres with size of 100 nm. A single FePdCu island was formed on the top of each SiO2 nanosphere. The structure of the obtained system was studied by x-r...
1708.01057v1
2017-08-17
Three Phase-Grating Moire Neutron Interferometer for Large Interferometer Area Applications
We demonstrate a three phase-grating neutron interferometer as a robust candidate for large area interferometry applications and characterization of materials. This novel far-field moire technique allows for broad wavelength acceptance and relaxed requirements related to fabrication and alignment, circumventing the mai...
1708.05421v1
2017-08-23
A Review of Smart Materials in Tactile Actuators for Information Delivery
As the largest organ in the human body, the skin provides the important sensory channel for humans to receive external stimulations based on touch. By the information perceived through touch, people can feel and guess the properties of objects, like weight, temperature, textures, and motion, etc. In fact, those propert...
1708.07077v2
2017-08-28
Elastic impact of a sphere with an elastic half-space: numerical modeling and comparison with experiment
Numerical simulations of the dynamics of an elastic collision between a rigid sphere and an elastic half-space are carried out. We assume an Amontons-Coulomb frictional force with a fixed coefficient of friction between the contacting surfaces during the impact. As a result of modeling a dimensionless function, describ...
1708.08531v1
2017-08-29
Element-resolved ultrafast demagnetization rates in ferrimagnetic CoDy
Femtosecond laser induced ultrafast magnetization dynamics have been studied in multisublattice CoxDy1-x alloys. By performing element and time-resolved X-ray spectroscopy, we distinguish the ultrafast quenching of Co3d and Dy4f magnetic order when the initial temperatures are below (T=150K) or above (T=270K) the tempe...
1708.08918v2
2017-08-29
Ultrafast hot-electron induced quenching of Tb4f magnetic order
We have investigated ultrafast quenching of the Tb4f magnetic order in Co74Tb26 alloys, induced by femtosecond hot-electrons pulses. The hot-electron pulses were produced in specific non-magnetic capping layers by infrared fs laser pulses. Our experimental results show that sub-picosecond dynamics of Tb4f magnetic mome...
1708.08919v2
2017-09-06
The MRO-accompanied modes of Re-implantation into SiO2-host matrix: XPS and DFT based scenarios
The following scenarios of Re-embedding into SiO2-host by pulsed Re-implantation were derived and discussed after XPS-and-DFT electronic structure qualification: (i) low Re-impurity concentration mode -> the formation of combined substitutional and interstitial impurities with Re2O7-like atomic and electronic structure...
1709.01673v1
2017-08-28
Organic and perovskite solar cells for space applications
For almost sixty years, solar energy for space applications has relied on inorganic photovoltaics, evolving from solar cells made of single crystalline silicon to triple junctions based on germanium and III-V alloys. The class of organic-based photovoltaics, which ranges from all-organic to hybrid perovskites, has the ...
1709.01787v2
2017-09-08
Higher Sobolev Regularity of Convex Integration Solutions in Elasticity: The Dirichlet Problem with Affine Data in $\text{int}(K^{lc})$
In this article we continue our study of higher Sobolev regularity of flexible convex integration solutions to differential inclusions arising from applications in materials sciences. We present a general framework yielding higher Sobolev regularity for Dirichlet problems with affine data in $\text{int}(K^{lc})$. This ...
1709.02880v1
2017-09-15
A Thermoelastoplastic Material Model for Finite-Strain Cyclic Plasticity of Metals
In this paper we present a thermodynamically consistent material model which is capable of modelling ductile-to brittle failure mode transition in ductile material undergoing deformations at high strain rates, and demonstrate the performance of the model in a numerical study using a fully coupled thermal-structural fin...
1709.05416v1
2017-09-21
Zero-Field Quantum Critical Point in Ce$_{0.91}$Yb$_{0.09}$CoIn$_5$
We present results of specific heat, electrical resistance, and magnetoresistivity measurements on single crystals of the heavy-fermion superconducting alloy Ce$_{0.91}$Yb$_{0.09}$CoIn$_5$. Non-Fermi liquid to Fermi liquid crossovers are clearly observed in the temperature dependence of the Sommerfeld coefficient $\gam...
1709.07161v3
2017-09-22
A Co(II)-based Molecular Magnet with a 6 T Coercive Field
Hard magnets with high coercivity, such as Nd2Fe14B and SmCo5 alloys, can maintain magnetisation under a high reverse external magnetic field and have therefore become irreplaceable parts in many practical applications. Molecular magnets are promising alternatives, owing to their precise and designable chemical structu...
1709.07697v2
2017-09-22
On Extracting Mechanical Properties from Nanoindentation at Temperatures up to 1000$^{\circ}$C
Alloyed MCrAlY bond coats, where M is usually cobalt and/or nickel, are essential parts of modern turbine blades, imparting environmental resistance while mediating thermal expansivity differences. Nanoindentation allows the determination of their properties without the complexities of traditional mechanical tests, but...
1709.07714v1
2017-08-09
Metal passivation effect on focused beam-induced nonuniform structure changes of amorphous SiOx nanowire
Passivation effect of heterogeneous Au nanoparticles (AuNPs) on the nonuniform structure changes of amorphous SiOx nanowire (a-SiOx NW) as athermally induced by focused electron beam (e-beam) irradiation is investigated in an in-situ transmission electron microscope. It is found that at room temperature the straight an...
1709.07920v1
2017-09-29
Grain-size dependent electric-field induced structural changes in relaxor-ferroelectric based unclamped piezoelectric grains
Polymer-piezoceramic 0-3 composites combine the flexibility of the polymers and the excellent piezoelectric properties of the ferroelectric based ceramic. While grain size of the ceramic powder is one of the important considerations in the fabrication of such composites, a correlation relating poling field induced stru...
1709.10231v1
2017-11-06
Local Lorentz force and ultrasound Doppler velocimetry in a vertical convection liquid metal flow
We report velocity measurements in a vertical turbulent convection flow cell that is filled with the eutectic liquid metal alloy gallium-indium-tin by the use of local Lorentz force velocimetry (LLFV) and ultrasound Doppler velocimetry (UDV). We demonstrate the applicability of LLFV for a thermal convection flow and re...
1711.01837v1
2017-11-07
Identifying interatomic potentials for the accurate modeling of interfacial segregation and structural transitions
Chemical segregation and structural transitions at interfaces are important nanoscale phenomena, making them natural targets for atomistic modeling, yet interatomic potentials must be fit to secondary physical properties. To isolate the important factors that interatomic potentials must capture in order to accurately m...
1711.02693v2
2017-11-09
The search for high entropy alloys: a high-throughput $\textit{ab-initio}$ approach
While the ongoing search to discover new high-entropy systems is slowly expanding beyond metals, a rational and effective method for predicting "in silico" the solid solution forming ability of multi-component systems remains yet to be developed. In this article, we propose a novel high-throughput approach, called "LTV...
1711.03426v2
2017-11-17
Atom Probe Analysis of Ex Situ Gas-Charged Stable Hydrides
In this work, we report on the atom probe tomography analysis of two metallic hydrides formed by pressurized charging using an ex situ hydrogen charging cell, in the pressure range of 200-500 kPa (2-5 bar). Specifically we report on the deuterium charging of Pd/Rh and V systems. Using this ex situ system, we demonstrat...
1711.06667v1
2017-11-20
Computational analysis of short-range interactions between an edge dislocation and an array of equally-spaced identical shearable or non-shearable precipitates
The interaction between dislocations and precipitates plays an important role in the mechanical behavior of alloys. To provide more insight into the physics of this interaction, this research analyzes short-range interactions of an edge dislocation with an array of equally-spaced identical precipitates. We use a modifi...
1711.07428v2
2017-11-29
Tuning topological surface magnetism by bulk alloying
Deploying an analytical atomistic model of the bulk band structure of the IV-VI semiconductors we connect the spin structure of the topological surface state to the crystal field and spin orbit coupling parameters of the bulk material. While the Dirac-Weyl (or equivalently, Rashba) type topological surface state is oft...
1711.10760v1
2017-12-07
Grain boundary complexions and the strength of nanocrystalline metals: Dislocation emission and propagation
Grain boundary complexions have been observed to affect the mechanical behavior of nanocrystalline metals, improving both strength and ductility. While an explanation for the improved ductility exists, the observed effect on strength remains unexplained. In this work, we use atomistic simulations to explore the influen...
1712.02829v2
2017-12-10
Combining phase field crystal methods with a Cahn-Hilliard model for binary alloys
During phase transitions certain properties of a material change, such as composition field and lattice-symmetry distortions. These changes are typically coupled, and affect the microstructures that form in materials. Here, we propose a 2D theoretical framework that couples a Cahn-Hilliard (CH) model describing the com...
1712.03503v1
2017-12-10
Mid infrared two-photon absorption in a room-temperature extended-wavelength InGaAs photodetector
We investigate the nonlinear optical response of a commercial extended-wavelength In$_{0.81}$Ga$_{0.19}$As photodetector. Degenerate two-photon absorption in the mid-infrared range is observed at room temperature using a quantum cascade laser emitting at $\lambda=4.5~\mu$m as the excitation source. From the measured tw...
1712.03580v1
2017-12-11
Level spacing and Poisson statistics for continuum random Schrödinger operators
We prove a probabilistic level-spacing estimate at the bottom of the spectrum for continuum alloy-type random Schr\"odinger operators, assuming sign-definiteness of a single-site bump function and absolutely continuous randomness. More precisely, given a finite-volume restriction of the random operator onto a box of li...
1712.03925v3
2017-12-19
Alloy formation at the bottom and top Fe interfaces of Ti/Fe/Ti trilayers
The chemical mixing at the Fe-on-Ti and Ti-on-Fe, i.e. the bottom and top interfaces of Fe in atomically deposited layers, were studied experimentally and by molecular dynamics simulations of the layer growth. The basic structure and chemical composition of the layers were explored in cross-sections using transmission ...
1712.06870v1
2017-12-19
Strain-induced effects in the electronic and spin properties of a monolayer of ferromagnetic GdAg2
We report on the structural, electronic and magnetic properties of a monolayer of GdAg2, forming a moir\'e pattern on Ag(111). Combining scanning tunneling microscopy and ab-initio spin-polarized calculations, we show that the electronic band structure can be shifted linearly via thermal dependent strain of the intra-l...
1712.06974v1
2017-12-27
Observation of Al41Sm5: new evidence for structural hierarchy in Al-Sm alloys
Using an effective genetic algorithm, we uncover the structure of a metastable Al41Sm5 phase that supplements its family sharing similar short-range orders. The phase evolves upon heating an amorphous Al-9.7at.%Sm ribbon, produced by melt-spinning. The dynamical phase selection is discussed with respect to the structur...
1712.09638v1