Role of electron-electron and electron-phonon interaction effect in the optical conductivity of VO2

TL;DR

This study investigates how electron-electron and electron-phonon interactions influence the optical conductivity of VO2, revealing a temperature-dependent broad peak in the insulating phase linked to electron-phonon coupling.

Contribution

It provides new insights into the charge dynamics and the role of interactions in VO2's metal-insulator transition through optical measurements.

Findings

Metal-insulator transition observed in optical conductivity

Broad Drude-like structure in metallic phase

Temperature-dependent broad peak in insulating phase

Abstract

We have investigated the charge dynamics of VO2 by optical reflectivity measurements. Optical conductivity clearly shows a metal-insulator transition. In the metallic phase, a broad Drude-like structure is observed. On the other hand, in the insulating phase, a broad peak structure around 1.3 eV is observed. It is found that this broad structure observed in the insulating phase shows a temperature dependence. We attribute this to the electron-phonon interaction as in the photoemission spectra.