Electronic structure and properties of pure and doped ε -FeSi from ab initio local-density theory

摘要: Local-density calculations of the electronic structure FeSi, ${\mathrm{FeSi}}_{1\ensuremath{-}x}{\mathrm{Al}}_{x},$ and ${\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Ir}}_{x}\mathrm{Si}$ systems in B20 are presented. Pure FeSi has a semiconducting gap 6 mRy at 0 K. Effects temperature (T) terms vibrational excitations included. Various measurable properties, such as magnetic susceptibility $\ensuremath{\chi}(T),$ specific heat $C(T),$ thermoelectric power $S(T),$ relative variations resistivity $\ensuremath{\rho}(T),$ peak positions density states (DOS) calculated. The feedback from disorder onto is found to be essential for good description most although results $S(T)$ undoped can described up about 150 K without considerations disorder. Above this T, only filling due accompanied by exchange enhancement, explain large susceptiblity. overall agreement with experimental data properties doped pure suggests that system well local-density approximation even T. Doped quite rigid-band shifts Fermi energy on DOS FeSi. Spin polarization Ir-doped leads semimetallic state low