Numerical solution of the t-J model with random exchange couplings in d=infinity dimensions

TL;DR

This paper presents a numerically exact solution to the t-J model with random exchange couplings in infinite dimensions, revealing an incoherent metallic state near the Mott transition with distinct excitation bands.

Contribution

It extends the CT-QMC method to handle vector bosonic fields coupled to local spins, enabling precise analysis of the t-J model with randomness in high dimensions.

Findings

Incoherent metal with residual magnetic moments near Mott transition

Existence of an additional excitation band separated from the Hubbard band

Insights into the metallic state in disordered strongly correlated systems

Abstract

To explore the nature of the metallic state near the transition to a Mott insulator we investigate the t-J model with random exchange interaction in d=infinity dimensions. A numerically exact solution is obtained by an extension of the continuous-time quantum Monte Carlo (CT-QMC) method to the case of a vector bosonic field coupled to a local spin. We show that the paramagnetic solution near the Mott insulator describes an incoherent metal with a residual moment, and that single-particle excitations produce an additional band, which is separated from the Mott-Hubbard band.