Thermodynamics of a bad metal-Mott insulator transition in the presence of frustration

Abstract

We study a range of thermodynamic properties (charge susceptibility, specific heat, entropy and spin susceptibility) of the Hubbard model on the anisotropic triangular lattice at half filling by means of the numerical finite-temperature Lanczos method. We observe clear signatures of a metal-Mott insulator transition in the charge susceptibility, and show that the metallic phase is characterized by a small charge susceptibility, large entropy, low coherence temperature, large renormalized quasiparticle mass, and large spin susceptibility. We show that the local magnetic moment in the metallic phase is large and comparable to the local moment in the insulating phase. These are all characteristics of bad metallic behavior. In addition, we show how frustration increases the density of low-lying spin excitations in the Mott insulating phase and decreases longer range spin correlations.