%0 Journal Article
%A Juan Li
%A Xinyue Zhang
%A Zhiwei Chen
%A Siqi Lin
%A Wen Li
%A Jiahong Shen
%A Ian T Witting
%A Alireza Faghaninia
%A Yue Chen
%A Anubhav Jain
%A Lidong Chen
%A G. G Jeffrey Snyder
%A Yanzhong Pei
%B Joule
%D 2018
%G eng
%N 5
%P 976 - 987
%R 10.1016/j.joule.2018.02.016
%T Low-Symmetry Rhombohedral GeTe Thermoelectrics
%V 2
%8 05/2018
%! Joule
%X <p><span>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.</span></p>