Dynamical thermal response functions for strongly correlated one-dimensional systems: Hubbard and spinless fermion t-V model

Abstract

In this paper, we study the thermal response functions for two one-dimensional models, namely, the Hubbard and spinless fermion t-V model, respectively. By exactly diagonalizing finite sized systems, we calculate dynamical, electrical, thermoelectrical, and thermal conductivities via the Kubo formalism [J. Phys. Soc. Jpn. 12, 570 (1957)]. The thermopower (Seebeck coefficient), Lorenz number, and dimensionless figure of merit are then constructed, which are quantities of great interest to the physics community both theoretically and experimentally. We also geometrically frustrate these systems and destroy integrability by the inclusion of a second-neighbor hop in the kinetic energy operator. These frustrated systems are shown to have enhanced thermopower and Lorenz number at intermediate and low temperatures.