Robust half-metallicities of alkali-metal-based half-Heusler compounds

Abstract

This paper aims to perform a systematic density functional study on alkali-metal-based halfHeusler compounds, namely ACrZ (A = Li, Na, and K; Z = As, Sb, and P), to identify the optimal half-metal (HM) for practical applications. Unlike most HMs proposed so far, the majority of ACrZ compounds in our study exhibit a wide band gap (1.60–2.38 eV) and retain robust halfmetallicity even at the surface. Furthermore, the half-metallicity is robust under severe strain, up to 10%. Because of their stability, robust half-metallicity at the surface and under strain, and good lattice mismatch with zinc-blende semiconductors, we propose LiCrZ and NaCrZ (Z = As and Sb) as promising compounds for practical applications to spintronics.