Cyclotron resonance of electrons in the Wigner solid regime

Abstract

The authors have studied the cyclotron resonance (CR) of high-mobility 2D electron systems in the extreme quantum limit. Beyond the fractional quantum Hall regime, below a critical filling factor (vc approximately=1/9), an additional CR line with a mass completely independent of temperature is observed on the high-energy side of the conventional CR. A total condensation into the novel state occurs at temperatures below 1 K. The determined energy gap ( approximately=4 K) separating this lowered ground state from the free carrier state breaks down above vc. This new phase is discussed in terms of a magnetically induced Wigner crystal.