Effects of Antisite Defects on Seebeck Coefficient in Fe_2VAl -- Analyses based on Bipolar Random Anderson Model
arXiv:2507.00497 · doi:10.7566/JPSJ.94.094603
Abstract
A microscopic mechanism is proposed for a dramatic sign change of the Seebeck coefficient from positive to negative sign by the introduction of antisite defects in FeVAl based on bipolar random Anderson model (BPRAM), which incorporates hybridization effects between randomly distributed antisites and host bands, where the valence and conduction bands are treated separately due to their separation in momentum space. Applying a self-consistent T-matrix approximation, we find that antisite defects in FeVAl induce new states in the band overlap region, resulting in a scattering rate that is higher for hole carriers in the valence band than that for electron carriers in the conduction band, leading to negative Seebeck coefficient. This mechanism of sign change presents a potential new approach for controlling thermoelectric properties in semimetallic systems without changing carrier concentration.
arXiv comment7 pages, 8 figures, to be published in J. Phys. Soc. Jpn. vol. 94, (2025)
References in corpus (6)
- Excitonic Correlations in the Intermetallic Fe2VAl
- Electronic Structure, Local Moments and Transport in Fe_2VAl
- Electronic and thermoelectric properties of Fe2VAl: The role of defects and disorder
- Unexpected band gap increase in the Fe2VAl Heusler compound
- Influence of disorder on the transport properties of heavy-fermion systems
- Quantum-Many-Body Intermetallics: Phase Stability of FeAl and Small-Gap Formation in FeVAl