Thermoelectric response of single quintuple layer sodium copper chalcogenides persisting at high temperature.

The thermoelectric transport properties of two-dimensional (2D) layered NaCuX (X = S, Se) are investigated by employing first-principles based Boltzmann transport theory. Single quintuple NaCuX layers have a relatively large Seebeck coefficient (), electrical conductivity () and hence power factor (PF = ) for a p-type heavy doped region due to the valence band degeneracy. The largely reduced by dominant polar scattering leads to a PF up to 0.