Megagauss Cyclotron Resonance and Quantum Hall Effect of 2D Electron Gas in HgCdMnTe

Two-dimensional electron gas adjacent to a grain boundary in bicrystal of narrow-gap semiconductor p- Hg$\text{}_{0.79}$Cd$\text{}_{0.19}$Mn$\text{}_{0.02}$Te has been studied under ultra strong impulse magnetic fields (up to 140 T). Both cyclotron resonance and quantum Hall effect are measured for the same samples. The values of the resonance fields point to strong nonparabolicity. A broadening of the line is interpreted in terms of an intersubband mixing that occurs for the upper Landau level. A steep increase in the linewidth in the field range 20-30 T, which coincides with a strong decrease in the Hall resistance is assigned to the field-induced metal-insulator transition in our system.