Low-Symmetry Rhombohedral GeTe Thermoelectrics

Date Published
05/2018
Publication Type
Journal Article
Authors
DOI
10.1016/j.joule.2018.02.016
Abstract

Thermoelectric materials enable a heat flow to be directly converted to a flow of charge carriers for generating electricity. The crystal structure symmetry is one of the most fundamental parameters determining the properties of a crystalline material including thermoelectrics. The common belief currently held is that high-symmetry materials are usually good for thermoelectrics, leading to great efforts having historically been focused on GeTe alloys in a high-symmetry cubic structure. Here we show a slight reduction of crystal structure symmetry of GeTe alloys from cubic to rhombohedral, enabling a rearrangement in electronic bands for more transporting channels of charge carriers and many imperfections for more blocking centers of heat-energy carriers (phonons). This leads to the discovery of rhombohedral GeTe alloys as the most efficient thermoelectric materials to date, opening new possibilities for low-symmetry thermoelectric materials.

Journal
Joule
Volume
2
Year of Publication
2018
Issue
5
Pagination
976 - 987
ISSN Number
25424351
Short Title
Joule
Refereed Designation
Refereed
Organizations
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