Single parabolic band behavior of thermoelectric p-type Cu4Mn2Te4

Semiconducting Cu4Mn2Te4, consisting of nontoxic elements only, attracts increasing attentions as a promising thermoelectric material due to its low lattice thermal conductivity. This work focuses on systematic investigation of thermoelectric properties for Cu4Mn2Te4 to assess its potential for thermoelectric applications. Hall carrier concentration ranging from 9 × 1020 cm−3 to 16 × 1020 cm−3 is obtained by various dopants, which enables a reasonable assessment of electronic transport properties by a single parabolic band model with acoustic scattering. The lowest lattice thermal conductivity of ∼0.4 W/m-K at high temperature is obtained, which presumably results from weak bonding for Cu and large number (20) of atoms in primitive cell. As a result, a peak zT of 0.6 is realized here. On the basis of the model, a peak zT as high as 1.0 is achievable for this compound when the Hall carrier concentration is reduced to 3-4 × 1020 cm−3. This work not only demonstrates Cu4Mn2Te4 as a potentially high-performance thermoelectric material, but also provides a well understanding of its underlying physical parameters.