Evolution of spectral function in a doped Mott insulator : surface vs. bulk contributions

TL;DR

This paper investigates how the spectral function of a doped Mott insulator evolves with hole doping, revealing a bulk-to-surface transition and challenging existing theories, with an empirical model based on U/W.

Contribution

It provides new experimental insights into the spectral evolution and introduces an empirical description using a single parameter, U/W, to explain the observations.

Findings

Bulk-to-surface metal-insulator transition observed

Doping effects inconsistent with existing theories

Empirical U/W parameter describes spectral evolution

Abstract

We study the evolution of the spectral function with progressive hole doping in a Mott insulator, $La_{1-x}Ca_xVO_3$ with $x$ = 0.0 - 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.