Electronic structure, transport, and phonons of $\mathrm{SrAg}Ch\mathrm{F}$ ($Ch = \mathrm{S}$, Se, Te): Bulk superlattice thermoelectrics

Electronic structure, transport, and phonons of $SrAg C h F$ ( $C h = S$ , Se, Te): Bulk superlattice thermoelectrics

Vijay Kumar Gudelli, V. Kanchana, G. Vaitheeswaran, David J. Singh, A. Svane, N. E. Christensen, and Subhendra D. Mahanti

Phys. Rev. B 92, 045206 – Published 15 July 2015

Abstract

We report calculations of the electronic structure, vibrational properties, and transport for the $p$ -type semiconductors, $SrAg C h F$ ( $C h = S$ , Se, and Te). We find soft phonons with low frequency optical branches intersecting the acoustic modes below $50 {cm}^{- 1}$ , indicative of a material with low thermal conductivity. The bands at and near the valence-band maxima are highly two-dimensional, which leads to high thermopowers even at high carrier concentrations, which is a combination that suggests good thermoelectric performance. These materials may be regarded as bulk realizations of superlattice thermoelectrics.

Received 5 March 2015

DOI:https://doi.org/10.1103/PhysRevB.92.045206

Authors & Affiliations

Vijay Kumar Gudelli and V. Kanchana^*

Department of Physics, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram-502 205, Telangana, India

G. Vaitheeswaran^*

Advanced Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Prof. C. R. Rao Road, Gachibowli, Hyderabad-500 046, Telangana, India

David J. Singh