LiPbSb<sub>3</sub>S<sub>6</sub>: A Semiconducting Sulfosalt with Very Low Thermal Conductivity
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Abstract
The
new semiconductor LiPbSb<sub>3</sub>S<sub>6</sub> crystallizes in
the space group <i>P</i>2<sub>1</sub>/<i>c</i>. The structure is a member of the lillianite homologous series and
is composed of layers of PbS archetype Sb/Li–S separated by
trigonal-prismatic-coordinated Pb/Li. Electronic band structure calculations
indicate an indirect band gap, with direct gaps lying very close in
energy. LiPbSb<sub>3</sub>S<sub>6</sub> has one of the lowest thermal
conductivities seen in a crystalline material, ∼0.24 W m<sup>–1</sup> K<sup>–1</sup> at room temperature, and a
high resistivity, ∼4 × 10<sup>9</sup> Ω·cm,
and exhibits strong light absorption with a nearly direct band gap
of 1.6 eV
