High thermoelectric performance can be achieved in two-dimensional (PbTe)2 layer

Publication date: Available online 8 October 2019Source: Physics Letters AAuthor(s): Caiyu Sheng, Dengdong Fan, Huijun LiuAbstractThe electronic, phonon and thermoelectric transport properties of (PbTe)2 layer are investigated by using first-principles pseudopotential method combined with Boltzmann transport equation. We demonstrate that there is a valley degeneracy of six for the top valence band, which leads to larger carrier concentration and thus higher electrical conductivity without obvious reduction in the Seebeck coefficient. Moreover, the intrinsic van der Waals interactions between neighboring Pb layers induce additional phonon scattering and thus ultrasmall lattice thermal conductivity. As a consequence, ZT>2.0 can be realized in a wide temperature region from 650 to 1000 K with a maximum value of 3.0. Interestingly, we find almost identical n- and p-type ZT when the temperature ranges from 300 K to 800 K.

Source: Physics Letters A - October 10, 2019 Category: Physics Source Type: research