Electronic Structure of Paramagnetic V_2O_3: Strongly Correlated Metallic and Mott Insulating Phase

TL;DR

This study uses LDA+DMFT with quantum Monte Carlo to analyze the electronic structure of V_2O_3 across metallic and Mott insulating phases, revealing new insights into the transition and resolving a longstanding puzzle.

Contribution

It provides a detailed computational analysis of V_2O_3's electronic phases, highlighting the role of orbital degrees of freedom in the Mott transition.

Findings

Quasiparticle weight increases at room temperature compared to high temperature.

The Mott-Hubbard transition in V_2O_3 differs from the one-band Hubbard model.

The small Mott gap in Cr-doped V_2O_3 is explained.

Abstract

LDA+DMFT, the computation scheme merging the local density approximation and the dynamical mean-field theory, is employed to calculate spectra both below and above the Fermi energy and spin and orbital occupations in the correlated paramagnetic metallic and Mott insulating phase of V_2O_3. The self-consistent DMFT equations are solved by quantum Monte Carlo simulations. Room temperature calculations provide direct comparison with experiment. They show a significant increase of the quasiparticle height in comparison with the results at 1160 K. We also obtain new insights into the nature of the Mott-Hubbard transition in V_2O_3. Namely, it is found to be strikingly different from that in the one-band Hubbard model due to the orbital degrees of freedom. Furthermore we resolve the puzzle of the unexpectedly small Mott gap in Cr-doped V_2O_3.