Spin-Cyclotron Resonance in n-Type Indium Antimonide at Low Temperatures

An interpretation of known experimental data on magnetic resonance measurements in tellurium-doped n-type indium antimonide crystals with compensation ratio K ≈ 0.1 of tellurium (hydrogen-like donors) by zinc (hydrogenlike acceptors) at 10 MHz frequency in a quantizing external magnetic field with induction from 0.17 to 1.70 T at liquid-helium temperature is proposed. It is revealed that the observed resonance is caused by the absorption of energy quanta of radio-frequency (10 MHz) radiation by c-band electrons. The electron transition between adjacent Landau levels is mediated by the electric component of the radio wave, while transitions between Zeeman sublevels are driven by its magnetic component. The number of absorbed radio-frequency quanta at resonance increases from 3.9∙10⁴ to 1.6∙10⁵ with c-band electron concentrations from 6∙10¹⁵ to 5∙10¹⁸ cm^–3 at an approximately constant compensation ratio. Calculations show that the width of the magnetic resonance lines (from peak to peak of the first derivative of the radio-wave absorption signal with respect to the external magnetic field) is determined by fluctuations in the potential energy of electrons in the crystals due to their doping and compensation.