Orbital-selective confinement effect of Ru $4d$ orbitals in SrRuO${}_3$ ultrathin film

Abstract

The electronic structure of SrRuO${}_3$ thin film with thickness from 50 to 1 unit cell (u.c.) is investigated via the resonant inelastic x-ray scattering (RIXS) technique at the O K-edge to unravel the intriguing interplay of orbital and charge degrees of freedom. We found that orbital-selective quantum confinement effect (QCE) induces the splitting of Ru $4d$ orbitals. At the same time, we observed a clear suppression of the electron-hole continuum across the metal-to-insulator transition (MIT) occurring at the 4 u.c. sample. From these two clear observations we conclude that QCE gives rise to a Mott insulating phase in ultrathin SrRuO${}_3$ films. Our interpretation of the RIXS spectra is supported by the configuration interaction calculations of RuO${}_6$ clusters.

7 pages, 7 figures

References in corpus (1)

• Structural, electronic and magnetic properties of SrRuO${}_3$ under epitaxial strain

Cited by in corpus (1)

• Phase Instability amid Dimensional Crossover in Artificial Oxide Crystal