  Thermoelectric materials open a way to harness dissipated energy and make
electronic devices less energy-demanding. Heat-to-electricity conversion
requires materials with a strongly suppressed thermal conductivity but still
high electronic conduction. This goal is largely achieved with the help of
nanostructured materials, even if the bulk counterpart is not highly efficient.
In this work, we investigate how thermoelectric efficiency is enhanced by
many-body effects in graphene nanoribbons at low temperature. To this end,
starting from the Kane-Mele-Hubbard model within a mean-field approximation, we
carry out an extensive numerical study of the impact of electron-electron
interactions on the thermoelectric efficiency of graphene nanoribbons with
armchair or zigzag edges. We consider two different regimes, namely trivial and
topological insulator. We find that electron-electron interactions are crucial
for the appearance of interference phenomena that give rise to an enhancement
of the thermoelectric efficiency of the nanoribbons. Lastly, we also propose an
experimental setup that would help to test the validity of our conclusions.
