Computational investigation of inverse Heusler compounds for spintronics applications

Abstract

First-principles calculations of the electronic structure, magnetism and structural stability of inverse-Heusler compounds with the chemical formula X2YZ are presented and discussed with a goal of identifying compounds of interest for spintronics. Compounds for which the number of electrons per atom for Y exceed that for X and for which X is one of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, or Cu; Y is one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, or Zn; and Z is one of Al, Ga, In, Si, Ge, Sn, P, As or Sb were considered. The formation energy per atom of each compound was calculated. By comparing our calculated formation energies to those calculated for phases in the Inorganic Crystal Structure Database (ICSD) of observed phases, we estimate that inverse-Heuslers with formation energies within 0.052 eV/atom of the calculated convex hull are reasonably likely to be synthesizable in equilibrium. The observed trends in the formation energy and relative structural stability as the X, Y and Z elements vary are described. In addition to the Slater-Pauling gap after 12 states per formula unit in one of the spin channels, inverse-Heusler phases often have gaps after 9 states or 14 states. We describe the origin and occurrence of these gaps. We identify 14 inverse-Heusler semiconductors, 51 half-metals and 50 near half-metals with negative formation energy. In addition, our calculations predict 4 half-metals and 6 near half-metals to lie close to the respective convex hull of stable phases, and thus may be experimentally realized under suitable synthesis conditions, resulting in potential candidates for future spintronics applications.

Designing chemical analogs to PbTe with intrinsic high band degeneracy and low lattice thermal conductivity

“…1. We count Li 2 InBi as synthesizable compound since such small convex hull distance is well within the threshold of Heusler compounds 23,24 .

Fig. 1Crystal and electronic structures.

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Structural, Electronic, Magnetic, and Elastic Properties of CoX′CrZ (X′ = Sc, Ti; Z = Al, Ga) Quaternary Heusler Alloys: First‐Principles Study

“…Here, it is considered that if one of the spin channels of a compound has a small enough pseudo‐gap at the Fermi level or a gap close enough to the Fermi level (a threshold value that is small enough or close enough is defined as 0.30 eV, ≈0.20 electronic states per formula unit), then the compound can be considered as nearly half‐metal. [ 60 ] The spin‐down channels of CoScCrAl and CoScCrGa do not pass through the Fermi level, and the bandgaps are 0.52 and 0.56 eV, respectively, and it is also obvious that they are both indirect bandgaps.…”

Ab initio calculations of conduction band effective mass parameters of thermoelectric $${\hbox {Mg}}_{2} {\hbox {X}}_{1{-}x} {\hbox {Y}}_x$$ (X, Y = Si, Ge, Sn) alloys

“…In turn, DFT formation energies have been widely useful to predict stable and meta-stable structures at using high-throughput computing and machine learning techniques 41,42 . Nonetheless, in order to study stability at room or higher temperatures, extra contributions coming from the entropy of phonons are present and possible phase transition may occur 43 .…”