Origin of the anomalous mass renormalization in metallic quantum well states of correlated oxide SrVO$_3$

TL;DR

This study uses ARPES to investigate SrVO$_3$ ultrathin films, revealing that the anomalous mass enhancement in quantum well states is mainly due to quasi-one-dimensional effects from orbital-selective quantization.

Contribution

It uncovers the origin of mass renormalization in SrVO$_3$ quantum well states, linking it to orbital-selective quantization and quasi-one-dimensional electron behavior.

Findings

Mass enhancement increases as subband bottom approaches Fermi level.

Electron correlation strength varies with subband energy.

Quasi-one-dimensional character causes the anomalous mass renormalization.

Abstract

$In$ $situ$ angle-resolved photoemission spectroscopy (ARPES) has been performed on SrVO$_3$ ultrathin films, which show metallic quantum well (QW) states, to unveil the origin of the anomalous mass enhancement in the QW subbands. The line-shape analysis of the ARPES spectra reveals that the strength of the electron correlation increases as the subband bottom energy approaches the Fermi level. These results indicate that the anomalous subband-dependent mass enhancement mainly arises from the quasi-one-dimensional character of confined V $3d$ states as a result of their orbital-selective quantization.