  We investigate nonlinear thermal transport properties of a single interacting
quantum dot with two energy levels tunnel-coupled to two electrodes using
nonequilibrium Green function method and Hartree-Fock decoupling approximation.
In the case of asymmetric tunnel-couplings to two electrodes, for example, when
the upper level of the quantum dot is open for transport, whereas the lower
level is blocked, our calculations predict a strong asymmetry for the heat
(energy) current, which shows that, the quantum dot system may act as a thermal
rectifier in this specific situation.
