Electron Cyclotron Resonance in Te at Very High Magnetic Fields

Abstract

Recently, many studies have been made of the valence band structure of Te [1]. As for the conduction band, however, much less experimental data have been obtained, because Te crystals are always p-type in the extrinsic region at low temperature. Previous studies of the conduction band structure have been made mainly through the interband magneto-absorption [2] and the cyclotron resonance [3] or the Shubnikov-de Haas effect [4] on the surface inversion layers. In undoped Te crystals, the Hall coefficient changes the sign at about 200 K, as the intrinsic carriers are thermally excited across the forbidden gap, reflecting the fact that the mobility of electrons is larger than that of holes [5]. Therefore, at temperature above 200 K, we would observe the cyclotron resonance of intrinsic electrons in the conduction band, if ω_cτ is large enough in high magnetic field [6]. In this paper, we report the cyclotron resonance in Te which was observed at room temperature in pulsed high magnetic fields up to the megagauss range [7].