Materials Literature
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The fundamental properties of valleys are recently attracting growing attention due to electrons in new and topical materials possessing this degree-of-freedom and recent proposals for valleytronics devices. In silicon MOSFETs, the interest has a longer history since the valley degree of freedom had been identified as…
We report on {\it ab initio} time-dependent spin dynamics simulations for a two-center magnetic molecular complex based on time-dependent non-collinear spin density functional theory. In particular, we discuss how the dynamical behavior of the {\it ab initio} spin-density in the time-domain can be mapped onto a model…
Recent density functional theory (DFT) calculations by F\"orst et al. [Phys. Rev. Lett. 96, 175501 (2006)] have predicted that vacancies in both low and high carbon steels have a carbon dimer bound to them. This is likely to change the thinking of metallurgists in the kinetics of the development of microstructures. Wh…
Transformation optics has shaped up a revolutionary electromagnetic design paradigm, enabling scientists to build astonishing devices such as invisibility cloaks. Unfortunately, the application of transformation techniques to other branches of physics is often constrained by the structure of the field equations. We de…
The experimentally obtained (Venkataraman {\em et al}. \cite{latha}) cosine squared relation of electronic conductance in a biphenyl molecule is verified theoretically within a tight-binding framework. Using Green's function formalism we numerically calculate two-terminal conductance as a function of relative twist an…
The high friction of diamondlike carbon (DLC) films in vacuum impedes achieving their application in space environment. Here we show that the vacuum friction coefficients can be lowered below 0.1 by avoiding formation of carbonaceous transfer layers on the counterfaces. First-principles calculations reveal that the lo…
Colloidal nanocrystals (NCs) of lead chalcogenides are a promising class of tunable infrared materials for applications in devices such as photodetectors and solar cells. Such devices typically employ electronic materials in which charge carrier concentrations are manipulated through "doping;" however, persistent elec…
Hemicellulose material is an abundant and relatively under-utilized polymeric material present in lignocellulosic materials. In this research, an alkaline treatment was applied to pinewood (PW), switchgrass (SG), and coastal bermuda grass (CBG) in order to extract hemicelluloses to subsequently produce a novel biosorb…
Recent advances in nanotechnology could facilitate the production of cheaper solar cells. This review describes synthetic routes to various nanostructured materials that are potentially useful in photovoltaic applications. We have focused on materials that are based on earth abundant elements and/or those that are hel…
A suspension of fine selenium powder (100 or 200 mesh) in octadecene (Se-SUS) has proven to be a high-performance, versatile, convenient, reproducible, yet green selenium precursor. The advantages of Se-SUS arise from its highly reactive chemical nature and flexibility. These two features made it possible to carry out…
A density functional theory study of the structural and electronic properties and relative stability of fluorinated sp 3 silicon nanotubes and their corresponding silicon nanowires built along various crystallographic orientations is presented. The structural stability is found to increase linearly with fluorine surfa…
Hybrid functionals and empirical correction schemes are compared to conventional semi-local density functional theory (DFT) calculations in order to assess the predictive power of these methods concerning the formation energy and the charge transfer level of impurities in the wide-gap semiconductor ZnO. While the gene…
By using laboratory x-ray photoemission spectroscopy (XPS) and hard x-ray photoemission spectroscopy (HX-PES) at a synchrotron facility, we report an empirical semi-quantitative relationship between the valence/core-level x-ray photoemission spectral weight and electrical conductivity in La1−xSrxMnO3 as a function of…
Manifestations of anomalous conductivity in polar dielectric films is demonstrated for the first time on samples of copolymer of vinylene and vinyl chloride, as was previously observed on modified PVC samples. On the base of these experimental results important new insights into the physical sense of traditionally use…
The kinetic theory of switching processes in crystalline ferroelectric materials under the influence of a variable external electric field is formulated. The basic equations are derived and their exact analytical solution at arbitrary time-dependent external field are obtained. Connection between the hysteresis loops…
The search for oxide-based room-temperature ferromagnetism has been one of the holy grails in condensed matter physics. Room-temperature ferromagnetism observed in Nb-doped SrTiO${}_{3}$ single crystals is reported in this Rapid Communication. The ferromagnetism can be eliminated by air annealing (making the samples p…
Magnetic properties of DyAl$_{0.926}$Cr$_{0.074}$O$_3$ and DyAlO$_3$ were studied. We found that both compounds are antiferromagnetic with a low Néel transition temperature. At higher temperatures the magnetic characteristics show a Curie-Weiss dependence. The Néel temperature disappears when a field of about 2 T is a…
The influence of La and Nd co-substitution on the structural and magnetic properties of BiFeO3 (BFO) thin films was examined. Epitaxial thin films of pure and, La and Nd co-doped BFO on the SrRuO3 buffered single crystal SrTiO3 (001) substrate were deposited using pulsed laser deposition. The structural change in co d…
Genetic algorithms (GAs) are a helpful tool in optimization, simulation, modelling, design, and prediction purposes in various domains of science including materials science, medicine, technology, economy, industry, environment protection, etc. Reported uses of GAs led to solving of numerous complex computational task…
Fully hydrogenated graphene (graphane) and partially hydrogenated graphene materials are expected to possess various fundamentally different properties from graphene. We have prepared highly hydrogenated graphene containing 5% wt of hydrogen via Birch reduction of graphite oxide using elemental sodium in liquid NH3 as…