Intrinsic Correlated Electronic Structure of CrO2 Revealed by Hard X-ray Photoemission Spectroscopy

TL;DR

This study uses bulk-sensitive hard x-ray photoemission spectroscopy to investigate the intrinsic electronic structure of CrO2, revealing correlated Mott-Hubbard behavior and recoil effects that influence spectral features.

Contribution

It provides new insights into the correlated electronic structure of CrO2 using HAXPES, highlighting recoil effects and intrinsic Mott-Hubbard correlations.

Findings

Evidence of a finite Fermi edge in CrO2

Spectral weight shift due to recoil effects

Estimated Coulomb correlation energy Uav ~ 3.2 eV

Abstract

Bulk-sensitive hard x-ray photoemission spectroscopy (HAXPES) reveals for as-grown epitaxial films of half-metallic ferromagnetic CrO2(100) a pronounced screening feature in the Cr 2p3/2 core level and an asymmetry in the O 1s core level. This gives evidence of a finite, metal-type Fermi edge, which is surprisingly not observed in HAXPES. A spectral weight shift in HAXPES away from the Fermi energy is attributed to single-ion recoil effects due to high energy photoelectrons. In conjunction with inverse PES the intrinsic correlated Mott-Hubbard-type electronic structure is unravelled, yielding an averaged Coulomb correlation energy Uav ~ 3.2 eV.