Cyclotron resonance in Kondo insulator

Abstract

Motivated by the recent experimental observations of quantum oscillations in the Kondo insulators SmB_{6} and YbB_{12}, we study magneto-optical conductivity of Kondo insulators. We show that there exist nontrivial cyclotron resonance peaks in a frequency domain below the hybridization gap as a result of the characteristic Landau level structure of the system. Furthermore, these low-energy peaks are enhanced near the insulator-metal phase transition driven by an applied magnetic field and stable even at low temperatures. They are smoothly connected via the Kondo effect to resonance peaks for unhybridized conduction and f electrons at high temperature. The nontrivial cyclotron resonance is a dynamical counterpart of quantum oscillations in static quantities, and through this intimate connection it will provide a useful insight for the latter.