First Principle Analysis of the Magnetism and Electronic Structure of Fe2XSi (X=Ti, V)
The electronic, magnetic, and mechanical properties of Fe2XSi, where X is titanium (Ti) and vanadium (V), are investigated using computational methods. Volume optimization reveals that the ground state of Fe2TiSi is a nonmagnetic narrow-band gap semiconductor, and that of Fe2VSi is a ferrimagnetic metal. The negative formation energies of both materials confirm the stability of their crystal structures. Mechanical properties confirm the static stability of the crystal structure and suggest that the titanium compound is ductile; however, the vanadium material is brittle. Density of states and band structure studies confirm the nonmagnetic semiconducting nature with an indirect band gap at {\Gamma} and X for the titanium material and the ferrimagnetic-metallic nature of the vanadium material. Electronic and magnetic properties of the materials were investigated with applied tension (negative pressure) and compression (positive pressure) to the crystal structure. The pressure study on Fe2TiSi shows a tunable band gap and a possible semiconductor-metal transition, and Fe2VSi shows a tunable magnetic moment and a possible low-spin/high-spin magnetic transition.