Atomistic simulation of Mott transition in fluid metals: Combining molecular dynamics with dynamical mean-field theory

TL;DR

This paper introduces a novel quantum molecular dynamics method combining real-space dynamical mean-field theory to simulate Mott transitions in fluid metals, revealing two distinct transition mechanisms linked to atomic bonding structures.

Contribution

The paper develops a new DMFT-based quantum MD approach capable of capturing correlation-driven Mott transitions in atomic liquids, extending the modeling of fluid metal electronic properties.

Findings

Identified two types of Mott transitions depending on atomic bonding.

Discovered a transition from molecular to atomic insulator with increased Hubbard repulsion.

Linked electron localization to cluster fragmentation and liquid-gas transition.

Abstract

We present a new quantum molecular dynamics (MD) method where the electronic structure and atomic forces are solved by a real-space dynamical mean-field theory (DMFT). Contrary to most quantum MD methods that are based on effective single-particle wave functions, the DMFT approach is able to describe correlation-induced Mott metal-insulator transitions and the associated incoherent electronic excitations in an atomic liquid. We apply the DMFT-MD method to study Mott transitions in an atomic liquid model which can be viewed as the liquid-state generalization of the Hubbard model. The half-filled Hubbard liquids also provide a minimum model for alkali fluid metals. Our simulations uncover two distinct types of Mott transition depending on the atomic bonding and short-range structures in the electronically delocalized phase. In the first scenario where atoms tend to form dimers, increasing the Hubbard repulsion gives rise to a transition from a molecular insulator to an atomic insulator with a small window of enhanced metallicity in the vicinity of the localization transition. On the other hand, for Hubbard liquids with atoms forming large conducting clusters, the localization of electrons leads to the fragmentation of clusters and is intimately related to the liquid-gas transition of atoms. Implications of our results for metal-insulator transitions in fluid alkali metals are discussed.