This work reports on three quaternary Heusler compounds NiFeMnGa, NiCoMnGa, and CuCoMnGa. In contrast to their ternary relatives, are still rarely investigated. A very large pool of interesting materials lies thus idle waiting for exploration. The difficulty consists in choosing prospective compositions, trial error is elaborate expensive. We have identified several candidates employing ab initioelectronic-structure calculations. were synthesized, the structural magnetic properties...

The quaternary intermetallic Heusler compounds CoFeMn$Z$ ($Z=\text{Al}$, Ga, Si, or Ge) with $1:1:1:1$ stoichiometry were predicted to exhibit half-metallic ferromagnetism by ab initio electronic structure calculations. synthesized using an arc-melting technique and the crystal structures analyzed x-ray powder diffraction. properties investigated hard photoelectron spectroscopy. low-temperature magnetic moments, as determined from magnetization measurements, follow Slater-Pauling rule,...

Semiconducting half- and, to a lesser extent, full-Heusler compounds are promising thermoelectric materials due their compelling electronic properties with large power factors. However, intrinsically high thermal conductivity resulting in limited efficiency has so far impeded widespread use practical applications. Here, we report the computational discovery of class hitherto unknown stable semiconducting ten valence electrons ($X_2YZ$, $X$=Ca, Sr, and Ba; $Y$= Au Hg; $Z$=Sn, Pb, As, Sb, Bi)...

Half-Heusler compounds $XYZ$ crystallize in the space group $F\overline{4}3m$ and can be viewed as a zinc-blende-like ${(YZ)}^{\ensuremath{-}}$ lattice partially filled with He-like ${X}^{+}$ interstitials. In this work, we investigated I-II-V (eight-electrons) half-Heusler by first-principles calculations order to find suitable semiconductors for optoelectronics such Cd-free buffer layer materials chalcopyrite-based thin-film solar-cell devices. We report systematic examination of band gaps...

A high power factor and low lattice thermal conductivity are two essential ingredients of highly efficient thermoelectric materials. Although monolayers transition metal dichalcogenides possess factors, conductivities significantly impede their practical applications. Our first-principles calculations show that these well fulfilled in the recently synthesized Pd$_{2}$Se$_{3}$ monolayer, whose crystal structure is composed [Se$_{2}$]$^{2-}$ dimers, Se$^{2-}$ anions, Pd$^{2+}$ cations...

The pursuit of thermoelectric materials poses a formidable challenge, given that numerous predicted candidates fail in real-world applications.

Elastic constants and their derived properties of various cubic Heusler compounds were calculated using the first-principles density functional theory. To begin with, Cu2MnAl is used as a case study to explain interpretation basic quantities compare them with experiments. The main part work focuses on Co2-based that are Co2MnM group elements M=Al, Ga, In, Si, Ge, Sn, Pb, Sb, Bi, Co2TM Al or 3d transition metals T=Sc, Ti, V, Cr, Mn, Fe. It found many correlate mass nuclear charge Z element....

Intermetallic compounds with sizable band gaps are attractive for their unusual properties but rare. Here, we present a new family of stable semiconducting quaternary Heusler compounds, designed based on the 18-electron rule and discovered by means high-throughput ab initio calculations rule. The 99 semiconductors reported here adopt ordered structure prototype LiMgSnPd (F4̅3m, No. 216) contain 18 valence electrons per formula unit. They realized filling void in half small electropositive...

Improving the figure of merit $zT$ thermoelectric materials requires simultaneously a high power factor and low thermal conductivity. An effective approach for increasing is to align band extremum achieve degeneracy ($\geq$ 12) near Fermi level as realized in PbTe [\textcolor{blue}{Pei et. al. \textit{Nature} 473, 66 (2010)}], which usually relies on structure engineering, e.g., chemical doping strain. However, very few could such without heavy or suffering impractical By employing...

Previous studies have shown that a large solid-state entropy of reduction increases the thermodynamic efficiency metal oxides, such as ceria, for two-step thermochemical water splitting cycles. In this context, configurational arising from oxygen off-stoichiometry in oxide, has been focus most previous work. Here we report different source entropy, onsite electronic coupling between orbital and spin angular momenta lanthanide f orbitals. We find is sizable all lanthanides, reaches maximum...

Post-Li batteries based on Na, K, Ca, and Mg offer compelling alternatives to Li ones, whose resources are scarce unevenly distributed in the earth's crust. However, development of these forthcoming is currently thwarted by lack cost-effective, nontoxic, highly efficient anode materials. To tackle this challenge, we employed a comprehensive structure search using minima hopping method, followed density functional theory (DFT) calculations. Our led an as-yet-unobserved metallic C7N monolayer...

The search for new energy harvesting materials that directly convert (waste) heat into electricity has received increasing attention. Transition metal oxides are a promising class of thermoelectric (TE) can operate at high temperature due to their chemical and thermal stability. However, the lattice conductivity, poor electrical low thermopower have significantly impeded applications date. Using first-principles calculations, we predict known oxide Bi2PdO4 be highly efficient hole-doped TE...

The Heusler compound CoTiSb was synthesized and investigated theoretically experimentally with respect to electronic structure optical, mechanical, vibrational properties. optical properties were in a wide spectral range from 10 meV 6.5 eV compared ab initio calculations. spectra confirm the semiconducting nature of CoTiSb, strong exciton absorption at 1.83 eV. calculated phonon dispersion as well elastic constants verify mechanical stability cubic $C{1}_{b}$ system. Furthermore, solid...

Over the past decade, tremendous effort has been made to improve light-harvesting ability of push–pull porphyrin dyes. Despite notable success achieved in this direction, dyes still suffer from a poor efficiency owing lack absorption between Soret and Q-bands. To tackle issue, here we design series with anchoring groups either at meso- or β-position using calculations based on first-principles time-dependent density functional theory. In contrast common perception, find that bearing an...

The pursuit of efficient thermoelectric (TE) materials poses a formidable challenge, where the delicate balance inherently conflicting material properties is key to elevating figure merit (zT). Here, we tackle this challenge by exploiting offbeat chemistry tellurium atoms (Te). Through comprehensive first-principles calculations, identify group synthesized Te-based ABTe3 (A metal and B nonmetal element) compounds (bearing perovskite formula but not in nature), unique Te allows formation...

UHV-deposited films of the mixed phase tetramethoxypyrene and tetracyanoquinodimethane (TMP1-TCNQ1) on gold have been studied using ultraviolet photoelectron spectroscopy (UPS), X-ray-diffraction (XRD), infrared (IR) scanning tunnelling (STS). The formation an intermolecular charge-transfer (CT) compound is evident from appearance new reflexes in XRD (d1= 0.894 nm, d2= 0.677 nm). A softening CN stretching vibration (red-shift by 7 cm-1) TCNQ visible IR spectra, being indicative a CT order...

Within the huge family of Heusler compounds only a few quaternary derivatives are known that crystallize in space group. In this work, yet unreported CoRhMnZ (Z = Ga, Sn, Sb) and alloy Co0.5Rh1.5MnSb were investigated detail by experimental techniques theoretical methods. The ab initio calculations predict to be half-metallic ferromagnets or close ferromagnetic state. Calculations elastic constants show cubic structure is stable containing Mn. Both experiment reveal Mn cannot exchanged Fe...

In the present work, elastic constants and derived properties of tetragonal Heusler compounds were calculated using high accuracy full-potential linearized augmented plane wave (FPLAPW) method. To find criteria required for an accurate calculation, consequences increasing numbers k-points waves on convergence explored. Once calculated, anisotropies, sound velocities, Debye temperatures, malleability, other measurable physical determined studied systems. The suggested metallic bonding with...

Heteroanionic compounds that contain more than one type of anion have many unique and attractive properties, which make them desirable for numerous applications. However, because challenges in synthesis the complexity their phase spaces, heteroanionic are much less explored traditional homoanionic (single-anion) compounds. In this work, we perform a systematic screening synthesizable, stable, oxysulfide, oxyselenide, oxytelluride ABXO (A B metals; X = S, Se, Te) using high-throughput density...

Realizing green hydrogen generation is contingent on developing low-cost, ecofriendly, and viable photocatalysts for water splitting. Using first-principles screening, we filtered out several Ba-based double perovskites (i.e., Ba2BB′O6) that are desired such applications. Detailed chemical electronic structure analyses reveal all of the studied perovskites, despite their disparate compositions, fall into five classes, depending orbital occupancy B B′ cations. Of different class I with =...

An efficient approach to improve the thermoelectric performance of materials is converge their electronic bands, which known as band engineering. In this regard, lots effort has been made further efficiency bulk and exfoliated monolayers Bi2Te3 Sb2Te3. However, ultrahigh degeneracy thus significant improvement power factor have not yet realized in these materials. Using first-principles methods, we demonstrate that valley Sb2Te3 can be largely improved upon substitution middle-layer Te atoms...

The search for new thermoelectric materials that directly convert (waste) heat into electricity is a high-cost and time-consuming experimental effort. To facilitate this process, we perform systematic screening synthesizable stable ABQ3 (A B are metals; Q = S, Se) compounds using first-principles density functional theory calculations. A total of 40 predicted to be highly competent with nontoxic earth-abundant advantages. calculated power factors some them (e.g., n-type SnHfS3, p-type...