heat transport of the 2D single-band Hubbard model

We investigate the thermal conductivity and specific heat of the 2D Hubbard model using the numerically exact determinant quantum Monte Carlo algorithm and maximum entropy analytic continuation. At half filling, both specific heat and thermal conductivity show peaks at temperature scales related to the Hubbard interaction energy U and spin superexchange energy J. We identify two kinds of contributions to the specific heat and the thermal conductivity: one which involves the local kinetic energy and another which involves the interaction term. At low temperatures, where the charge degrees of freedom are gapped-out, the contribution to both specific heat and the thermal Drude weight associated with the kinetic energy agree well with spin-wave theory for the spin-1/2 antiferromagnetic Heisenberg model. In the metallic phase, we describe the evolution of the thermal conductivity with temperature and doping and contrast it with the electrical conductivity and the specific heat.