Electronic structure and transport properties of Cu-deficient kuramite Cu3-xSnS4

TL;DR

This study investigates the electrical and thermal transport properties of Cu-deficient kuramite Cu3-xSnS4, revealing metallic conduction and reduced thermal conductivity, with insights from crystallography and density functional theory.

Contribution

It provides new insights into the transport properties of Cu-deficient kuramite and its potential as a thermoelectric material, highlighting the effects of Cu deficiency and cation disorder.

Findings

Metallic conduction observed with resistivity of 0.4 mΩ·cm at 300 K

Lattice thermal conductivity calculated at 2.6 W/m·K

Valence band involves hybridization of Cu 3d and S 3p orbitals

Abstract

Electrical and thermal transport properties of Cu-deficient kuramite Cu3-xSnS4 (CTS) was examined as a possible earth-abundant thermoelectric material. Crystallographic structure of CTS was characterized by partial disorder between Cu and Sn. In contrast to semiconducting electrical transport of related compounds, such as Cu2ZnSnS4 and Cu3SbS4, metallic conduction with an electrical resistivity of 0.4 mohmcm and a carrier concentration of 3 \times 10^21 cm-3 was observed at 300 K. Lattice thermal conductivity was calculated at 2.6 Wm^-1K^-1, which was probably reduced by Cu-deficiency and or partial cation disorder. Density functional theory calculation indicates valence band was composed of hybridization between Cu 3d orbitals and S 3p orbitals.