In past decades the scientific community has been looking for a reliable first-principles method to predict electronic structure of solids with high accuracy. Here we present an approach which call quasiparticle self-consistent $GW$ approximation. It is based on kind perturbation theory, where self-consistency constructed minimize perturbation. We apply it selections from different classes materials, including alkali metals, semiconductors, wide band gap insulators, transition metal oxides,...

Based on the concept of band bending at metal/semiconductor interfaces as an energy filter for electrons, we present a theory enhancement thermoelectric properties semiconductor materials with metallic nanoinclusions. We show that Seebeck coefficient can be significantly increased due to strongly energy-dependent electronic scattering time. By including phonon scattering, find $ZT$ electron is important high doping, while low doping it primarily decrease in thermal conductivity.

We present a new kind of self-consistent GW approximation based on the all-electron, full-potential linear muffin-tin orbital method. By iterating eigenfunctions Hamiltonian, self-consistency in both charge density and quasiparticle spectrum is achieved. explain why this form should be preferred to conventional one. Some results for Si (a representative semiconductor) are presented. Finally we consider many details electronic structure antiferromagnetic insulators MnO NiO. Excellent...

We have developed a type of self-consistent scheme within the $GW$ approximation, which we call quasiparticle (QS$GW$). shown that QS$GW$ describes energy bands for wide range materials rather well, including many where local-density approximation fails. contains physical effects found in other theories such as $\mathrm{LDA}+U$, self-interaction correction, and satisfactory manner without their drawbacks (partitioning itinerant localized electrons, adjustable parameters, ambiguities double...

From a partial-differential eigenproblem, without use of dipole approximation, we show that the eigenmodes (surface plasmons) disordered nanosystems (modeled as random planar composites) are not universally Anderson localized, but can have properties both localized and delocalized states simultaneously. Their topology is determined by separate small-scale "hot spots" distributed coherent over length may be comparable to total size system. Coherence lengths oscillator strengths vary orders...

We predict and quantitatively evaluate the unique possibility of concentrating energy an ultrafast excitation a nanosystem in small part whole system by means coherent control (phase modulation exciting ultrashort pulse). Such concentration is due to dynamic properties surface plasmons leads local fields enhanced orders magnitude. This effect exists for both "engineered" random nanosystems. also discuss possible applications.

Spin-transfer-torque magnetic random-access memory (STT-MRAM) is one of the leading emerging technologies for nonvolatile memory. Key to its development identifying materials with sufficient perpendicular anisotropy (PMA). The authors describe general mechanism tetragonal distortion in Heusler compounds, a class promising STT-MRAM, over 2000 members. This study offers guidance finding alloys high PMA.

We use an all-electron implementation of the GW approximation to analyze several possible sources error in theory and its implementation. Among these are convergence polarization Green's functions, dependence QP levels on choice basis sets, differing approximations for dealing with core levels. In all calculations presented here, G W generated from local-density (LDA), which we denote as \GLDA\WLDA approximation. To test range validity, is applied a variety materials systems. show that...

Abstract Although high-tunnelling spin polarization has been observed in soft, ferromagnetic, and predicted for hard, ferrimagnetic Heusler materials, there no experimental observation to date of magnetoresistance the latter. Here we report preparation highly textured, polycrystalline Mn 3 Ge films on amorphous substrates, with very high magnetic anisotropy fields exceeding 7 T, making them technologically relevant. However, small negative tunnelling that find is attributed predominant from...

In the present work we developed an orbital coupling model for cubic full Heusler compounds that provides a unified set of rules account chemical ordering, magnetic moment, and composition most promising candidates half-metallicity. The origin limitations are clearly described. To best our knowledge all several dozen half-metallic known in literature follow ${M}_{t}={N}_{t}\ensuremath{-}24$ or ${M}_{t}={N}_{t}\ensuremath{-}28$ generalized Slater-Pauling behavior satisfy derived...

In the present work we suggest a recipe for finding tetragonal Heusler compounds with perpendicular magnetic anisotropy (PMA) that also exhibit large tunneling magnetoresistance (TMR) when used as electrodes in tunnel junction devices suitable barrier materials. We performed density-functional theory calculations 286 and identified 116 stable compounds. Ten of these are predicted to have strong PMA and, simultaneously, exponentially increasing TMR thickness due so-called Brillouin zone spin...

Abstract Magnetic random-access memory that uses magnetic tunnel junction cells is a high-performance, non-volatile technology goes beyond traditional charge-based memories. Today, its speed limited by the high magnetization of storage layer. Here we prepare devices with low ferrimagnetic Heusler alloy Mn 3 Ge as layer on technologically relevant amorphous substrates using combination nitride seed and chemical templating We switch state nanosecond long write pulses at reliable error rate 10...

We present an ab initio method for calculation of the electronic structure and transport nanoscale systems coupled to electrodes with applied voltage bias. The is based on local density approximation functional theory implemented in framework tight-binding linear muffin-tin orbital approach its atomic sphere approximation. A fully atomistic description nanosystem used, self-consistent charge electrostatic potential system under bias calculated using nonequilibrium Green's function (NEGF)...

We present an ab initio method for electronic structure calculations of materials at finite temperature (FT) based on the all-electron quasiparticle self-consistent $\mathit{GW}$ $(\mathrm{QPSC}\mathit{GW})$ approximation and Keldysh time-loop Green's function approach. apply to Si, Ge, GaAs, InSb, diamond show that band gaps these universally decrease with increasing in contrast results local density (LDA) functional theory where increase. At temperatures a few eV difference between...

The 'Brillouin zone spin filtering' mechanism of enhanced tunneling magnetoresistance (TMR) is described for magnetic tunnel junctions (MTJ) and studied on an example the MTJ with hcp Co electrodes hexagonal BN (h-BN) spacer. Our calculations based local density approximation functional theory (LDA-DFT) Co(0001)/h-BN/Co(0001) predict high TMR in this device due to Brillouin filtering mechanism. Owning specific complex band structure h-BN spin-dependent conductance system ultra-sensitive...

The field of online advertising, in essence, deals with the problem presenting ads to users most appropriate contexts achieve a multitude advertiser goals. A vast amount work advertising has been focused on optimizing banner display campaigns where main goal lies direct response metrics, often as clicks or conversions. In this paper, we explore newly popularized space video brand recognition is key focus. We propose framework based feedback mechanism optimize multiple specific performance...

We have developed a quasiparticle self-consistent GW method (QSGW), which is new to calculate the electronic structure within approximation. The formulated based on idea of perturbation; non-interacting Green function G(0), starting point for GWA obtain G, determined self-consistently so as minimize perturbative correction generated by GWA. After self-consistency attained, we W (the screened Coulomb interaction) and G self-consistently. This G(0) can be interpreted optimum propagator...

Antiferromagnet spintronic devices eliminate or mitigate long-range dipolar fields, thereby promising ultrafast operation. For spin transport electronics, one of the most successful strategies is creation metallic synthetic antiferromagnets, which, to date, have largely been formed from transition metals and their alloys. Here, we show that antiferrimagnetic sandwiches can be using exchange coupling spacer layers composed atomically ordered RuAl ultrathin, perpendicularly magnetized,...

We present nanometer-scale resolution, ballistic electron emission microscopy (BEEM) studies of Au/octanedithiol/n-GaAs (001) diodes. The presence the molecule dramatically increases BEEM threshold voltage and displays an unusual transport signature as compared to reference Au/GaAs Furthermore, images indicate laterally inhomogeneous interfacial structure. calculations that address role molecular layer at interface. Our results spatially resolved measurements add new insight using...

Nonmagnetic Cu2TiAl (CTA) Heusler compound is proposed as a new spacer material for all-Heusler alloy current-perpendicular-to-plane giant magnetoresistance devices based on first-principle calculations. The (001)-orientated Co2Mn(Ge0.75Ga0.25) (CMGG)/CTA/CMGG epitaxial pseudo spin valve (PSV) grown MgO(100) single crystal substrate showed relatively large MR output, ΔRA∼5.4 mΩ μm2, which comparable to that of the CMGG/Ag/CMGG PSV prepared with same condition. Considering short diffusion...

Realization of sub‐10 nm spin‐based logic and memory devices relies on the development magnetic materials with perpendicular anisotropy that can provide low switching current large thermal stability simultaneously. In this work, authors report one promising candidate, Fe 16 N 2 , a heavy‐metal‐free, non‐interface material demonstrate perpendicularly magnetized current‐perpendicular‐to‐plane (CPP) giant magnetoresistance (GMR) device based . The crystalline‐based in CPP GMR is measured to be...

Magnetic random access memory that uses magnetic tunnel junction cells is a high performance, non-volatile technology goes beyond traditional charge-based memories. Today its speed limited by the magnetization of storage layer. Here we show fast and highly reliable switching possible using very low ferrimagnetic Heusler alloy, Mn3Ge. Moreover, tunneling magnetoresistance highest yet achieved for material at ambient temperature. Furthermore, devices were prepared on technologically relevant...