Pressure tuning of thermoelectric performance in FeNbSb

Thermoelectric materials offer an ideal solution for the global energy crisis and environmental pollution as which can directly convert waste heat into electricity. From the view of device application, achieving large figure of merit zT at room temperature is highly desirable. Here, we choose a half-Heusler compound FeNb_0.8Ti_0.2Sb with a maximum zT of 1.1 at 1100 K as an example. By using the developed techniques for the high-pressure measurements, we investigate the potential of pressure to tune the thermoelectric performance at room temperature. An obvious improvement of zT by about 62.5 % is achieved at 4 GPa. A pressure-induced electronic topological transition is proposed to contribute to such an improvement. This study points to a promising avenue to enhance the zT of half-Heusler compounds.