Rare earth-based quaternary Heusler compoundsMCoVZ(M= Lu, Y;Z= Si, Ge) with tunable band characteristics for potential spintronic applications

Abstract

Magnetic Heusler compounds (MHCs) have recently attracted great attention since these types of material provide novel functionalities in spintronic and magneto-electronic devices. Among the MHCs, some compounds have been predicted to be spin-filter semiconductors [also called magnetic semiconductors (MSs)], spin-gapless semiconductors (SGSs) or half-metals (HMs). In this work, by means of first-principles calculations, it is demonstrated that rare earth-based equiatomic quaternary Heusler (EQH) compounds with the formula MCoVZ (M = Lu, Y; Z = Si, Ge) are new spin-filter semiconductors with total magnetic moments of 3 m B . Furthermore, under uniform strain, there are physical transitions from spin-filter semiconductor (MS) ! SGS ! HM for EQH compounds with the formula LuCoVZ, and from HM ! SGS ! MS ! SGS ! HM for EQH compounds with the formula YCoVZ. Remarkably, for YCoVZ EQH compounds there are not only diverse physical transitions, but also different types of spin-gapless feature that can be observed with changing lattice constants. The structural stability of these four EQH compounds is also examined from the points of view of formation energy, cohesive energy and mechanical behaviour. This work is likely to inspire consideration of rare earthbased EQH compounds for application in future spintronic and magnetoelectronic devices.

Perovskite R{\bar 3}c phase AgCuF3: multiple Dirac cones, 100% spin polarization and its thermodynamic properties

“…The general spin polarization ratio can be estimated as ¼ " À # = " þ # , in which " and # represent the spin-up states and spin-down states, respectively, extracted from the TDOS spectrum. AgCuF 3 possesses 100% spin polarization, which is important if it is to be used to generate a fully spin-polarized current for next-generation spintronic device applications (Wang et al, 2017).…”

Electronic structure, mechanical, thermoelectric, optical, and thermodynamic properties of yttrium‐based quaternary Heusler alloys

“…6,7 Similarly, they also possess tunable electronic structure and high Curie temperatures. Similarly, MCoVZ (M = Lu, Y; Z = Si, Ge) studied by Wang et al 20 found the strain controls and changes the physical nature and electronic properties in them. Investigation of spin polarization and band structure in HA has been done in the past by many authors [16][17][18][19] and had found the ScFeCrT (T = Si, Ge), YRhTiGe, CoMnYZ (Z = Al, Ga, In), and FeRuCrP (FeRhCrP)-based HAs as half-metals.…”

Site-Preference, Electronic, Magnetic, and Half-Metal Properties of Full-Heusler Sc2VGe and a Discussion on the Uniform Strain and Tetragonal Deformation Effects

“…To determine the stability of XA-type Sc 2 VGe compound, the cohesive energy (E c ) was calculated. The E c per unit cell can be expressed using the following formula [50]:…”

“…In addition, formation energy (E f ) is another way to describe the stability of crystals. We use the following formula to characterize E f per unit cell of Sc 2 VGe [50]:…”