Effect of tetragonal lattice distortion on the spin-gapless semiconducting characteristics of the inverse Heusler compound
Phys. Rev. B 112, 144439 – Published 28 October, 2025
DOI: https://doi.org/10.1103/822w-yxk6
Abstract
The effect of tetragonal distortion on spin-gapless semiconducting (SGS) behavior in thin films of inverse Heusler compound was investigated by first-principles calculations. Cubic exhibits SGS characteristics with a 0.7-eV energy gap in the spin-down band and a zero-width gap in the spin-up band, consistent with prior studies. Substrate-induced tetragonal distortion in thin film, arising from lattice mismatch, profoundly impacts its electronic structure and stability. Owing to the energy preference, volume-relaxed tetragonal distortion models align more closely with experimental observations. The weakened interatomic covalent hybridization due to tetragonal distortion is responsible for the volume expansion and decreased phase stability. Notably, robust half-metallicity persists across a broad distortion range, as evidenced by stable integer magnetic moments and preserved band gaps near the Fermi level. This magnetic stability stems from distortion-dependent moment compensation between Co and Ti/Si atoms. By contrast, the SGS state survives only within a narrow distortion level window (), beyond which valence and conduction bands cross the Fermi level, destroying the spin-gapless feature. The associated energy penalty for maintaining these characteristics within this window was modest (22–27 meV), suggesting that thermal annealing could enable films to overcome this barrier and approach more stable, less-distorted configurations. Therefore, current study provides suggestions to grow high-quality thin-film samples for spintronic applications by selecting suitable substrate to obtain the least lattice distortion, and annealing samples at high-enough temperature to endow samples with a more relaxed state. These results advance fundamental understanding of the effect of tetragonal distortion on SGS property and the related physics mechanism while offering practical strategies for developing high-performance spintronic devices.
