Electronic correlations and Hund's coupling effects in SrMoO$_3$ revealed by photoemission spectroscopy

TL;DR

This study explores how Hund's coupling influences electronic correlations in SrMoO3, revealing that it causes quasiparticle renormalization without band narrowing, supported by photoemission spectroscopy and advanced theoretical calculations.

Contribution

It demonstrates the significant role of Hund's rule coupling in quasiparticle renormalization in SrMoO3, distinct from traditional electron correlation effects.

Findings

Hund's coupling induces strong quasiparticle renormalization.

No observable band narrowing despite electron correlation signatures.

Identification of a plasmon satellite at -2 eV in spectra.

Abstract

We investigate the electronic structure of a perovskite-type Pauli paramagnet SrMoO3 (t2g2) thin film using hard x-ray photoemission spectroscopy and compare the results to the realistic calculations that combine the density functional theory within the local-density approximation (LDA) with the dynamical-mean field theory (DMFT). Despite the clear signature of electron correlations in the electronic specific heat, the narrowing of the quasiparticle bands is not observed in the photoemission spectrum. This is explained in terms of the characteristic effect of Hund's rule coupling for partially-filled t2g bands, which induces strong quasiparticle renormalization already for values of Hubbard interaction which are smaller than the bandwidth. The interpretation is supported by additional model DMFT calculations including Hund's rule coupling, that show renormalization of low-energy quasiparticles without affecting the overall bandwidth. The photoemission spectra show additional spectral weight around -2 eV that is not present in the LDA+DMFT. We interpret this weight as a plasmon satellite, which is supported by measured Mo, Sr and Oxygen core-hole spectra that all show satellites at this energy.