Ab-initio predictions of mechanical, electronic, magnetic, and transport properties of bulk and heterostructure of a novel Fe-Cr based full Heusler chalcogenide

According to electronic structure calculations based on density functional theory, we predicted and studied the structural, mechanical, electronic, magnetic, and transport properties of a new full Heusler chalcogenide called Fe₂CrTe in both its bulk and heterostructure forms. This system exhibits ferromagnetic and half-metallic (HM)-like behavior, with very high (about 95%) spin polarization at the Fermi level in its cubic phase. Interestingly, under tetragonal distortion, a clear minimum (with almost the same energy as the cubic phase) was found at a c/a value of ∼1.26, but it exhibits ferrimagnetic and fully metallic characteristics. The compound was found to be dynamically stable against lattice vibration in both phases. The elastic properties indicate that the compound is mechanically stable in both phases according to the stability criteria for the cubic and tetragonal phases. The elastic parameters demonstrate the mechanically anisotropic and ductile nature of the alloy system. Due to the HM-like behavior of the cubic phase and considering practical aspects, we probed the effect of strain and the substrate on various physical properties of the alloy. The transmission profile was calculated for the Fe₂CrTe/MgO/Fe₂CrTe heterojunction to investigate its possible use as a magnetic tunneling junction material in both the cubic and tetragonal phases. A large tunneling magnetoresistance ratio of ≈10³ % was determined for the tetragonal phase and it was one order of magnitude larger than that for the cubic phase.