Large Magneto-Transverse and Longitudinal Thermoelectric Effects in the Magnetic Weyl Semimetal TbPtBi

Magnetic topological semimetals provide new opportunities for power generation and solid-state cooling based on thermoelectric (TE) effect. The interplay between magnetism and nontrivial band topology prompts the magnetic topological semimetals to yield strong transverse TE effect, while the longitudinal TE performance is usually poor. Herein, it is demonstrated that the magnetic Weyl semimetal TbPtBi has high value for both transverse and longitudinal thermopower with large power factor (PF). At 300 K and 13.5 Tesla, the transverse thermopower and PF reach up to 214 mu V K-1 and 35 mu W cm(-1) K-2, respectively, which are comparable to those of state-of-the-art TE materials. Combining first-principles calculations, longitudinal magnetoresistance and planar Hall resistance measurements, and two-band model fitting, the large transverse thermopower and PF are attributed to both bipolar effect and large Hall angle. Moreover, the imperfectly compensated charge carriers and large transverse magnetoresistance induce the maximum magneto-longitudinal thermopower of 251 mu V K-1 with a PF of 24 mu W cm(-1) K-2 at 150 K and 13.5 Tesla, which is two times higher than that at zero magnetic field. This work demonstrates the great potential of topological semimetals for TEs and offers a new excellent candidate for magneto-TEs.

Automated summary

Magnetic topological semimetal TbPtBi exhibits excellent thermoelectric performance with high transverse and longitudinal thermopower as well as power factor. The large thermopower and power factor are attributed to the bipolar effect and large Hall angle. This discovery demonstrates the great potential of topological semimetals for thermoelectric applications and provides a new candidate for magneto-thermoelectrics.