de Visser Pieter J, Levallois Julien, Tran Michaël K, Poumirol Jean-Marie, Nedoliuk Ievgeniia O, Teyssier Jérémie, Uher Ctirad, van der Marel Dirk, Kuzmenko Alexey B
Department of Quantum Matter Physics, University of Geneva, Geneva 1211, Switzerland.
Kavli Institute of NanoScience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, Netherlands.
Phys Rev Lett. 2016 Jul 1;117(1):017402. doi: 10.1103/PhysRevLett.117.017402. Epub 2016 Jun 29.
We measure the far-infrared reflectivity and Kerr angle spectra on a high-quality crystal of pure semimetallic bismuth as a function of magnetic field, from which we extract the conductivity for left- and right-handed circular polarizations. The high spectral resolution allows us to separate the intraband Landau level transitions for electrons and holes. The hole transition exhibits 100% magnetic circular dichroism; it appears only for one polarization as expected for a circular cyclotron orbit. However, the dichroism for electron transitions is reduced to only 13±1%, which is quantitatively explained by the large effective mass anisotropy of the electron pockets of the Fermi surface. This observation is a signature of the mismatch between the metric experienced by the photons and the electrons. It allows for a contactless measurement of the effective mass anisotropy and provides a direction towards valley polarized magnetooptical pumping with elliptically polarized light.
