Thermopower of atomic-sized würtzite AlN wires

The thermopower of atomic-sized würtzite AlN wires coupled to Al(111) bulk contacts is investigated at low temperatures using Green–Keldysh formalism. We find that the conduction of the wide band-gap semiconductor wire is essentially enhanced by the presence of surface states. We show that the evanescent coupling to the surface states is strong enough to render thermopower of a few tens of μV/K, which may be enhanced by controlling the position of the surface states.