Cyclotron Resonance of Localized Electrons on a Si Surface

Cyclotron resonance of electrons in an inversion layer on a Si (100) surface is studied in the regime of low electron densities (nₛ<10¹² electrons/cm²). A distinct and sample-dependent shift of the resonance to lower magnetic field is observed as nₛ is decreased and electron localization is expected to occur. We give a simple interpretation of the effect in terms of electronic states bound in a harmonic-oscillator potential.