@article{Fan2024, 
author = {Yuting Fan and Chenghao Xie and Jun Li and Xiangyu Meng and Jinchang Sun and Jinsong Wu and Xinfeng Tang and Gangjian Tan},
title = {Engineering Thermoelectric Performance of α-GeTe by Ferroelectric Distortion},
year = {2024},
journal = {Energy & Environmental Materials},
volume = {7},
number = {2},
pages = {e12535},
keywords = {electronic band structures, ferroelectric distortion, lattice softening, thermoelectric, α-GeTe},
url = {https://www.sciopen.com/article/10.1002/eem2.12535},
doi = {10.1002/eem2.12535},
abstract = {The rhombohedral α-GeTe can be approximated as a slightly distorted rock-salt structure along its [1 1 1] direction and possesses superb thermoelectric performance. However, the role of such a ferroelectric-like structural distortion on its transport properties remains unclear. Herein, we performed a systematic study on the crystal structure and electronic band structure evolutions of Ge1-xSnxTe alloys where the degree of ferroelectric distortion is continuously tuned. It is revealed that the band gap is maximized while multiple valence bands are converged at x = 0.6, where the ferroelectric distortion is the least but still works. Once undistorted, the band gap is considerably reduced, and the valence bands are largely separated again. Moreover, near the ferro-to-paraelectric phase transition Curie temperature, the lattice thermal conductivity reaches its minima because of significant lattice softening enabled by ferroelectric instability. We predict a peak ZT value of 2.6 at 673 K in α-GeTe by use of proper dopants which are powerful in suppressing the excess hole concentrations but meanwhile exert little influence on the ferroelectric distortion.}
}