Electron-correlation effects on the properties of LaxSr1-xTiO3.

Abstract

A theoretical study of the electron-correlation effects on the properties of ${\mathrm{La}}_{\mathit{x}}$${\mathrm{Sr}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{TiO}}_{3}$ is presented. Using a single band repulsive Hubbard model employing the Gutzwiller approximation we study the effect of electron correlations on the effective-mass, band narrowing, plasma frequency, and spin susceptibility. The doping dependence of these properties are found to be qualitatively in agreement with recent experimental studies on ${\mathrm{La}}_{\mathit{x}}$${\mathrm{Sr}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{TiO}}_{3}$. We have also proposed a possibility for inducing superconductivity using the idea of proximity effect. The induced superconducting gap in ${\mathrm{La}}_{\mathit{x}}$${\mathrm{Sr}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{TiO}}_{3}$ is predicted to be maximum near the half-filling of the Ti 3d band.