Theory of optical spectral weights in Mott insulators with orbital degrees of freedom

TL;DR

This paper develops a unified theoretical framework to understand the optical spectral weights in Mott insulators with orbital degrees of freedom, linking optical properties to underlying spin and orbital correlations.

Contribution

It introduces partial sum rules for optical multiplet transitions and demonstrates their application to LaVO$_3$, revealing how optical spectra reflect spin-orbital physics.

Findings

Optical spectral weights depend on temperature and polarization due to spin and orbital correlations.

Optical data provides insights into orbital fluctuations and superexchange interactions.

The approach unifies magnetic and optical property analysis in transition metal oxides.

Abstract

Introducing partial sum rules for the optical multiplet transitions, we outline a unified approach to magnetic and optical properties of strongly correlated transition metal oxides. On the example of LaVO$_3$ we demonstrate how the temperature and polarization dependences of different components of the optical multiplet are determined by the underlying spin and orbital correlations dictated by the low-energy superexchange Hamiltonian. Thereby the optical data provides deep insight into the complex spin-orbital physics and the role played by orbital fluctuations.