Landau Quantization and Lifshitz Transition‐Modulated High Magneto‐Thermoelectric Performance

Abstract One of the necessary conditions for achieving high thermoelectric (TE) performance is the large longitudinal ( S xx ) and transverse thermopower ( S yx ), which are closely related to the Fermi level position and the energy‐dependent density of states (DOS) at the Fermi level. Herein, it is demonstrated that HfTe 5 has both high‐mobility induced significant quantum oscillations with an ultra‐low quantum limit of 2.7 T, and a significant Lifshitz transition where the Fermi level shows strong temperature dependence. The Landau levels yielded by the magnetic field distort the DOS with many equally‐spaced delta functions and significantly enhance the S xx and S yx . The drastically enhanced magneto‐longitudinal and transverse TE performance in HfTe 5 is achieved under an ultra‐low magnetic field of 1.4 T, which can be easily realized by a permanent magnet. Moreover, the Lifshitz transition further modulates its TE and magneto‐TE performance. Ultimately, the peak values of magneto‐longitudinal and transverse power factors ( PF ) reach 64 µW cm −1 K −2 at 150 K and 0.9 T and 19 µW cm −1 K −2 at 80 K and 1.4 T, respectively, which are comparable to the best TE materials such as Bi 2 Te 3 . This work provides novel methods and significant guidance for the development of TE and magneto‐TE materials.