Ultrahigh <i>zT</i> from strong electron–phonon interactions and a low-dimensional Fermi surface

Abstract

An ultrahigh zT of 2.7 at 700 K is achieved in a (Ge 0.86 Sb 0.08 Bi 0.06 )Te single crystal. This outstanding performance is attributed to one-dimensional-like electronic structure and the resulting strong electron–phonon interaction.