Suppressed reflectivity due to spin-controlled localization in a magnetic semiconductor

Abstract

The narrow gap semiconductor FeSi owes its strong paramagnetism to electron-correlation effects. Partial Co substitution for Fe produces a spin-polarized doped semiconductor. The spin-polarization causes suppression of the metallic reflectivity and increased scattering of charge carriers, in contrast to what happens in other magnetic semiconductors, where magnetic order reduces the scattering. The loss of metallicity continues progressively even into the fully polarized state, and entails as much as a 25% reduction in average mean-free path. We attribute the observed effect to a deepening of the potential wells presented by the randomly distributed Co atoms to the majority spin carriers. This mechanism inverts the sequence of steps for dealing with disorder and interactions from that in the classic Al'tshuler Aronov approach - where disorder amplifies the Coulomb interaction between carriers - in that here, the Coulomb interaction leads to spin polarization which in turn amplifies the disorder-induced scattering.

arXiv comment6 figures Submitted to PRB

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Cited by in corpus (8)

• Electrodynamics of Correlated Electron Materials
• Optical signatures of multifold fermions in the chiral topological semimetal CoSi
• History dependence of the magnetic properties of single-crystal Fe${}_{1-x}$Co${}_x$Si
• Electron-phonon interaction and spectral weight transfer in Fe${}_{1-x}$Co${}_x$Si
• Observation of Coherent Helimagnons and Gilbert damping in an Itinerant Magnet
• The importance of thermal disorder and electronic occupation for the T-dependence of the optical conductivity in FeSi and MnSi
• Optical evidence for heavy charge carriers in FeGe
• Spin excitations of the correlated semiconductor FeSi probed by THz radiation