A strategic high throughput search for identifying thermodynamically stable Li based half Heusler for spintronics application

Heusler alloys are potential candidates for spintronics applications. However, it is experimentally not feasible to identify the most efficient composition pertaining to their vast compositional space. Large-scale high throughput density functional theory (DFT) based calculations may aid in this. In this work, we perform high throughput DFT calculations on alkali metal-based half Heusler alloys; LiX_pY_1-pS (X, Y = V, Cr, Mn, Fe, Co, Ni and p = 0, 0.25, 0.5, 0.75, 1). We design systematic filters to select the energetically and vibrationally favorable compositions by considering the contributions stemming from the magnetic alignments of the ions. Thereby starting with 153 alloys, we down select 26 stable magnetic compositions, of which four were ferromagnetic, and eight were ferrimagnetic with 100 % spin polarization. Following this, we search for structural anisotropy, whereby tetragonal distortion is observed for one ferromagnetic and four antiferromagnetic alloys, with the possibility of having easy-axis magnetocrystalline anisotropy. The ferromagnetic LiFe_0.5Mn_0.5S and antiferromagnetic LiFeS are found to have the most prominent easy-axis magnetocrystalline anisotropy.