We extend the argument of Beni and Coll for the Hubbard model to show that the thermoelectric power of the lattice gas vanishes at concentration ½ because of particle-hole symmetry. This result is valid in the presence of phonon coupling, and, unlike the fermion case, is valid on close-packed as well as alternate lattices.

• Received 11 September 1978

DOI:https://doi.org/10.1103/PhysRevB.19.1302