Electronic structure of TiSi2.

Abstract

The linear augmented-plane-wave method has been applied to calculate the electronic structure and properties of the orthorhombic metastable base-centered (C49) and equilibrium face-centered (C54) phases of ${\mathrm{TiSi}}_{2}$. Despite the structural differences, both polytypes exhibit similar electronic properties, including broad low-lying Si 3s-3p bands, partially filled Ti 3d bands, and density-of-states minima within the 3d-band manifold near ${E}_{F}$. The high residual resistivity of C49 films in comparison with those having the C54 structure (\ensuremath{\sim}27 versus 0.7 \ensuremath{\mu}\ensuremath{\Omega} cm) is analyzed with the use of the calculated Drude plasma energy and Fermi velocity for the two polytypes. It is concluded that the comparatively short scattering length of the C49 phase (${l}_{c}$\ensuremath{\approxeq}90 A\r{} versus \ensuremath{\sim}990 A\r{} for C54 ${\mathrm{TiSi}}_{2}$) is an extrinsic property, caused primarily by the presence of heavily faulted microstructure in the C49 films.