  We investigate heat rectification in a two-qubit system coupled via the
Dzyaloshinskii-Moriya (DM) interaction. We derive analytical expressions for
heat currents and thermal rectification and provide possible physical
mechanisms behind the observed results. We show that the anisotropy of DM
interaction in itself is insufficient for heat rectification, and some other
form of asymmetry is needed. We employ off-resonant qubits as the source of
this asymmetry. We find the regime of parameters for higher rectification
factors by examining the analytical expressions of rectification obtained from
a global master equation solution. In addition, it is shown that the direction
and quality of rectification can be controlled via various system parameters.
Furthermore, we compare the influence of different orientations of the DM field
anisotropy on the performance of heat rectification. Finally, we investigate
the possible interplay between quantum correlations and the performance of the
quantum thermal rectifier. We find that asymmetry in the coherences is a
fundamental resource for the performance of the quantum thermal rectifier.
