Enhancement of thermoelectric performance across the topological phase transition in dense lead selenide

• Published in: Nature materials 2019-12, Vol.18 (12), p.1321-1326
• Main Authors: Chen, Liu-Cheng, Chen, Pei-Qi, Li, Wei-Jian, Zhang, Qian, Struzhkin, Viktor V., Goncharov, Alexander F., Ren, Zhifeng, Chen, Xiao-Jia
• Format: Article
• Language: English
• Subjects: 639/301; 639/301/299/2736; 639/766/119/2792/4128; Biomaterials; Chemistry; Chemistry and Materials Science; Chromium; Clean energy; Condensed Matter Physics; Crystal structure; Crystallinity; Density functional theory; Diamond anvil cells; Electricity consumption; Energy sources; External pressure; Figure of merit; Heat recovery; Insulators; Lead selenides; Magnetoresistance; Magnetoresistivity; Materials Science; Nanotechnology; Optical and Electronic Materials; Phase transitions; Physics; Pressure effects; Room temperature; Thermoelectric generators; Thermoelectric materials; Topology; Waste heat recovery; Waste recovery
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/s41563-019-0499-9

Alternative technologies are required in order to meet a worldwide demand for clean non-polluting energy sources. Thermoelectric generators, which generate electricity from heat in a compact and reliable manner, are potential devices for waste heat recovery. However, thermoelectric performance, as encapsulated by the figure of merit ZT, has remained at around 1.0 at room temperature, which has limited practical applications. Here, we study the effects of pressure on ZT in Cr-doped PbSe, which has a maximum ZT of less than 1.0 at a temperature of about 700 K. By applying external pressure using a diamond anvil cell, we obtained a room-temperature ZT value of about 1.7. From thermoelectric, magnetoresistance and Raman measurements, as well as density functional theory calculations, a pressure-driven topological phase transition is found to enable this enhancement. Experiments also support the appearance of a topological crystalline insulator after the transition. These findings point to the possibility of using compression to increase not just ZT in existing thermoelectric materials, but also the possibility of realizing topological crystalline insulators. By applying a pressure of 2.8 GPa using a diamond anvil cell, a topological phase transition is found to occur in Cr-doped PbSe. This enables a thermoelectric figure of merit ZT of 1.7 at room temperature.