Cyclotron resonance in InSb and GaAs with magnetic fields up to 140 T

Abstract

Pulsed magnetic fields generated by a capacitor discharge into a small single-turn coil are applied to measure cyclotron resonance in semiconductors in the infrared. The field waveform is a damped sine wave with a quarter period between 2 and 3 μsec whereafter the coil is violently destroyed by electromagnetic forces while the sample survives. The resonances are detected as intensity variations of laser light reflected off the sample surface. With 10.6-μm light from a C${\mathrm{O}}_2$ laser, resonances were found in InSb at fields of 27 ± 1, 39 ± 4, 61 ± 5, and 78 ± 6 T and in GaAs at 68 ± 3 and 94 ± 4 T. With 5.6-μm light from a CO laser one resonance was found in InSb at 85 ± 3 T. The resonances in InSb can be quantitatively interpreted as transitions between nonequally spaced Landau levels in the conduction band and are in agreement with Kane's theory.