Cyrstal field splitting and optical band gap of hexagonal LuFeO$_3$ films

TL;DR

This study investigates the crystal field splitting and optical band gap of hexagonal LuFeO$_3$ films using experimental spectroscopy and first-principles calculations, revealing specific energy splittings and a direct band gap around 2.0 eV.

Contribution

The paper combines experimental spectroscopy with theoretical calculations to accurately determine the crystal field splitting and optical band gap of hexagonal LuFeO$_3$ films, providing new insights into their electronic structure.

Findings

Crystal field splittings: 0.7 eV and 0.9 eV

Optical band gap: 2.0 eV

Theoretical band gap: 1.35 eV

Abstract

Hexagonal LuFeO$_3$ films have been studied using x-ray absorption and optical spectroscopy. The crystal splittings of Fe$^{3+}$ are extracted as $E_{e'}-E_{e"}$=0.7 eV and $E_{a_1'}-E_{e'}$=0.9 eV and a 2.0 eV optical band gap is determined assuming a direct gap. First-principles calculations confirm the experiments that the relative energies of crystal field splitting states do follow $E_{a_1'}>E_{e'}>E_{e"}$ with slightly underestimated values and a band gap of 1.35 eV.