Low Thermal Conductivity and Magneto-suppressed Thermal Transport in a Highly Oriented FeSb₂ Single Crystal

Abstract

Thermoelectric materials have been widely explored for the potential applications in power generation and refrigeration fields. High thermal conductivity (∼500 W/m K) of single-crystal FeSb2 limits the application in cryogenic cooling. In this work, the FeSb2 single crystal has been synthesized by the self-flux method. The rocking curve results reveal that the single crystal possesses quite high crystallinity. The micromorphology image shows that the single crystal is pyknotic without observable pores or cracks. Surprisingly, the thermal conductivity is reduced by 2 orders of magnitude compared with the previous reports, which can be attributed to the enhanced phonon scattering by the defects and impurities. Furthermore, the magnetic field can further suppress the thermal transport by reducing the phonon mean-free path. The maximum suppression rate of the thermal conductivity reaches 14% at 60 K when the magnetic field varies from 0 to 9 T. In this work, we have prepared the FeSb2 single crystal with low thermal conductivity, and the magneto-suppressed thermal transport strategy can be applied to other thermoelectric materials.

Recent progress of cryogenic thermoelectric materials

“…Strong electron correlations may cause semiconducting behavior with a narrow charge-excitation gap. It may be realized when a broad conduction band weakly hybridizes with a flat band arising from local atomic orbitals and, involving the Kondo exchange interaction between conduction electrons and local electrons [72] . Fig.…”

Self-Flux Method in Sputtered BiVO4 Films for Enhanced Photoelectrochemical Performance

“…The previous study suggests that the V 2 O 5 phase, which is one of the constituent elements of BiVO 4 , appears when V is rich in the films . In addition, the adjustment of self-flux in crystal growth has been successfully applied for improving crystal quality in other materials, , although this method has not been reported for the case of BiVO 4 growth yet. The self-flux technique is usually utilized in incongruent melting compounds to help crystal growth.…”

Dilute but significant: low cation concentration affects field dependent properties of Eu2Ga11Sn35

“…To the best of our knowledge, only a few reports exist of magneto-suppressed k in semiconductors. [43][44][45] Furthermore, such phenomena have not been observed in any other clathrate material to date. Typically, the change in k e due to magnetoresistance results in magneto-suppressed k in semimetals and narrow-gap semiconductors.…”