Evolution of Spectral Function in a Doped Mott Insulator: Surface vs Bulk Contributions

We study the evolution of the spectral function with progressive hole doping in a Mott insulator, ${\mathrm{La}}_{1-x}{\mathrm{Ca}}_x{\mathrm{VO}}_3$ with $x=0.0\mathrm{}–0.5$. The spectral features indicate a bulk-to-surface metal-insulator transition in this system. Doping dependent changes in the bulk electronic structure are shown to be incompatible with existing theoretical predictions. An empirical description based on the single parameter $U/W$ is shown to describe consistently the spectral evolution.