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

Junya Otsuki and Dieter Vollhardt

Accepted Monday Apr 22, 2013

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= 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.