MnTe2 as a novel promising thermoelectric material

Abstract

Semiconducting manganese ditelluride (MnTe2) crystalizes in a high symmetry cubic structure with sufficient band gap and consists of nontoxic elements only, therefore is focused on in this work for its potential thermoelectric applications. This material intrinsically comes with a very low hole concentration of 1019 cm−3, which can be successfully increased to 4 × 1020 cm−3 through Ag-doping at Mn site. Such a broad carrier concentration enables an effective optimization on thermoelectric power factor, and the doping process effectively reduces the lattice thermal conductivity down to ∼0.5 W/m-K due to the phonons scattered by additional point defects. As a result, a peak zT of ∼0.7 is obtained in p-type conduction. Moreover, the SPB model with acoustic scattering estimates the electronic properties well, which also enables insight into the underlying physical parameters related to the thermoelectric performance. Importantly, band structure calculation suggests a potentially higher thermoelectric performance for n-type conduction due to both higher band degeneracy and lower band effective mass. This work reveals MnTe2 is a novel promising thermoelectric material.