Spin excitations of the correlated semiconductor FeSi probed by THz radiation

Abstract

By direct measurements of the complex optical conductivity $\sigma (\nu )$ of FeSi we have discovered a broad absorption peak centered at frequency ${\nu }_0(4.2K)\approx 32c{m}^{-1}$ that develops at temperatures below 20 K. This feature is caused by spin-polaronic states formed in the middle of the gap in the electronic density of states. We observe the spin excitations between the electronic levels split by the exchange field of $H_e=34\pm 6T$. Spin fluctuations are identified as the main factor determining the formation of the spin polarons and the rich magnetic phase diagram of FeSi.

5 pages, 4 figures

References in corpus (3)

• Metal-insulator transition and magnetism in correlated band insulator: FeSi and Fe${}_{1-x}$Co${}_x$Si
• Electron-phonon interaction and spectral weight transfer in Fe${}_{1-x}$Co${}_x$Si
• The importance of thermal disorder and electronic occupation for the T-dependence of the optical conductivity in FeSi and MnSi

Cited by in corpus (2)

• Thermoelectricity in correlated narrow-gap semiconductors
• Correlated excited states in the narrow gap band semiconductor FeSi and antiferromagnetic screening of local spin moments