Vacancy defect control of colossal thermopower in FeSb2

Abstract

Iron diantimonide is a material with the highest known thermoelectric power. By combining scanning transmission electron microscope study with electronic transport neutron, X-ray scattering and first principle calculation we identify atomic defects that control colossal thermopower magnitude and nanoprecipitate clusters with Sb vacancy ordering which induce additional phonon scattering and substantially reduce thermal conductivity. Defects are found to cause rather weak but important monoclinic distortion of the unit cell Pnnm to Pm. The absence of Sb along [010] for high defect concentration forms conducting path due to Fe d orbital overlap. The connection between atomic defect anisotropy and colossal thermopower in FeSb2 paves the way for the understanding and tailoring of giant thermopower in related materials.

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Cited by in corpus (4)

• Optical conductivity and vibrational spectra of the narrow-gap semiconductor FeGa${}_3$
• Prototypical many-body signatures in transport properties of semiconductors
• Time-resolved measurement of Seebeck effect for superionic metals during structural phase transition
• Anisotropic Surface State Band Splitting and Low Energy Flat Bands in 3d Correlated Topological Kondo Insulator Candidate FeSb${}_2$