Effect Of Strain On The Electronic And Magnetic Properties Of Ti₂CrSi Alloy:a First-Principles Study

Spin-gapless semiconductors (SGSs) have been recently identified as a new class of functional materials that have potential applications in spintronic devices, thus they have attracted great attention. The SGS has a gap in the spin-down direction at the Fermi level similar to semiconductors, whereas it has a zero-width gap in the spin-up direction at the Fermi level. This made the conducting electrons and holes are not only 100% spin-polarized, but also excited easily. A lot of materials in the full-Heusler compounds have been found with properties of SGS. Using first-principles calculations, we investigate the band structures of full-Heusler Ti2CrSi alloy with an Hg2CuTi structure. Our calculated results show that the full-Heusler Ti2CrSi alloy is predicted as a promising candidate for SGS, and exhibits diverse electronic and magnetic properties under lattice distortions.The equilibrium lattice parameter was calculated to be 6.129 A. The full-Heusler Ti2CrSi alloy with the equilibrium lattice parameter is an anti-ferromagnetic semiconductor with a total magnetic moment that satisfies the Slater-Pauling rule M1=Z,-18. The calculated formation energy is-1.166 eV at the equilibrium lattice parameter, which suggests that the compound is thermodynamically stable and can be synthesized experimentally. By the density of states and band structure calculated, the electronic structure and magnetic property of Ti2CrSi alloy exhibits anti-ferromagnetic semiconductor (AFM-SM)â†'SGSâ†'half-metallic anti-ferromagnet (HM-AFM)â†'nonmagnetic semiconductor (NM-SM) or conventional ferrimagnet (FIM) transitions under lattice distortions. Ti2CrSi achieves an SGS feature at-2.0% and+11.4% uniform strains and at±1.8% tetragonal distortions. SGS to half-metallic anti-ferromagnet transitions occur at -2.4% and+11.8% uniform strains and at±2.2% tetragonal distortions. The half-metallic feature persists up to -5.3% and +13.5% uniform strains, as well at-9.3% and+13.2% tetragonal distortions. Ti2CrSi is a nonmagnetic semiconductor at a uniform strain of less than -5.3% and is a conventional ferrimagnet at larger than+13.5% uniform strains. Moreover, the alloy behaves as a conventional ferrimagnet, beyond the range of -9.3% to+13.2% tetragonal distortions. Because of the diverse electronic and magnetic properties, Ti2CrSi alloy has wide applications in the development of spintronic devices.