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HL: Fachverband Halbleiterphysik

HL 71: Transport Properties

HL 71.5: Vortrag

Donnerstag, 23. März 2017, 10:45–11:00, POT 112

Pressure-induced conduction band convergence in the thermoelectric ternary chalcogenide, CuBiS₂ — •Najebah Alsaleh, Elvis Shoko, and Udo Schwingenschlogl — King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia

The pressure dependence of electronic and thermoelectric properties of four ternary chalcogenides with space group Pnma, namely, CuSbS₂, CuSbSe₂, CuBiS₂, and CuBiSe₂ are investigated up to 10 GPa by using density functional theory combined with semiclassical Boltzmann theory. The effects of Van der Waals interactions are included in all calculations since these compounds have layered structures. All the compounds have indirect band gaps which decrease monotonically with increasing pressure except for CuBiS₂. For this compound, an indirect-indirect band gap switching occurs around 3 GPa leading to a conduction band convergence which appears to have important implications for thermoelectric properties. From a detailed examination of the structural changes in the different compounds, the unusual properties of CuBiS₂ are explained.