  The quantum dot arrays (QDAs) embedded into inhomogeneous nanowires connected
to metallic electrodes show an electron heat rectification effect, which is
attributed to the thermal voltage arising from a temperature bias and the QDA
with a broken spatial inversion symmetry. The staircase energy levels of QDAs
can be controlled to the resonant and off resonant transports for electrons in
the forward and backward temperature biases, respectively. The effect of
electron Coulomb interactions on the rectification efficiency of heat diode is
clarified by the case of double QDs. We find that it is important to reduce
phonon heat currents for implementing a high efficient electron heat diode at
high temperature.
