Anomalous mass enhancement in strongly-correlated quantum wells

TL;DR

This study uses dynamical-mean-field theory to analyze how strong electron correlations affect the subband structure and effective mass in quantum wells, revealing an anomalous mass enhancement linked to surface effects and long-range hoppings.

Contribution

It provides new insights into the subband-dependent mass enhancement in strongly correlated quantum wells, connecting theoretical predictions with recent experimental observations.

Findings

Effective mass increases as subband occupation decreases.

Surface layers and long-range hoppings amplify Coulomb effects.

Results align with recent photoemission experiments on SrVO3 films.

Abstract

Using dynamical-mean-field theory, we investigate the electronic properties of quantum wells consisting of a $t^1_{2g}$-electron system with strong correlations. The special focus is on the subband structure of such quantum wells. The effective mass is found to increase with increase in the value of the bottom of the subband, i.e., decrease in the subband occupation number. This is due to the combination of Coulomb repulsion, whose effect is enhanced on surface layers, and longer-range hoppings. We discuss the implication of these results for the recent angle-resolved photoemission experiment on SrVO$_3$ thin films.