Optical measurements of Landau level density of states and coulomb gaps under FQHE in Si MOSFET

• Published in: Surface science 1988, Vol.196 (1), p.196-208
• Main Authors: Kukushkin, I.V., Timofeev, V.B.
• Format: Article
• Language: English
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/0039-6028(88)90685-1

The density states (DOS) of 2D electrons in the accumulation channel of Si(001)-MOSFET under a transverse magnetic field has been investigated by means of radiative recombination spectra of 2D electrons with photoexcited holes. Oscillations of Landau level widths versus filling factor were observed and explained in terms of the screening of long-range random potential fluctuations due to charge centers in oxide by 2D electrons. An anomalous behaviour of the 2D c line spectral position under the condition of FQHE has been observed. From the magnitude of the jump of the spectral position of the 2D c line which corresponds to a discontinuity of the chemical potential of the system of interacting 2D electrons when their concentration changes in the vicinity of a fractional filling factor (namely ν= 7 3 , 8 3 ) the magnitudes of the gaps in the energy spectrum of the incompressible Fermi fluid have been determined. The experimental results suggest that the temperature dependence of condensation into an incompressible Fermi liquid displays a threshold-like behaviour. The critical temperature of condensation has been determined.