Study of a new layered ternary chalcogenide CuZnTe₂ and its potassium intercalation effect

<jats:title>Abstract</jats:title> <jats:p>A new layered ternary chalcogenide CuZnTe<jats:sub>2</jats:sub> and its effect due to potassium (K) intercalation have been investigated using <jats:italic>ab-initio</jats:italic> method under the framework of density functional theory (DFT). Here, we report the structural, electronic and elastic properties of both proposed parent compound CuZnTe<jats:sub>2</jats:sub> and intercalated KCuZnTe<jats:sub>2</jats:sub>. The electronic band structures and the density of states (DOS) of both these chalcogenides have also been studied. The parent compound demonstrates <jats:italic>p</jats:italic>-type conductivity with the energy band gap of 0.7 eV but surprisingly, the increase of energy gap (1.5 eV) is found in the intercalated KCuZnTe<jats:sub>2</jats:sub>, a direct-transition type semiconductor. The optical absorption result in KCuZnTe<jats:sub>2</jats:sub> also shows the identical value of gap energy calculated by Wood-Tauc theory. The density of states (DOS) in the valence band for both compounds is dominated by the partial contribution of Cu/Zn 3<jats:italic>d</jats:italic> and Te 5<jats:italic>p</jats:italic> orbitals but the prime contribution of Cu/Zn 4<jats:italic>s</jats:italic> and Te 5<jats:italic>s</jats:italic> mainly in the conduction band DOS. The DOS value at around Fermi level in these chalcogenides is indicating the degeneracy behavior of a semiconductor. Both compounds are mechanically stable and also malleable. We also calculated the thermal properties in the intercalated KCuZnTe<jats:sub>2</jats:sub> using quasi-harmonic Debye model. The observed values of Debye temperature, specific heat capacities and volume expansion coefficient using this model is almost consistent with the estimated values given in theory.</jats:p>