EDGE STATES IN THE FRACTIONAL QUANTUM HALL-EFFECT REGIME INVESTIGATEDBY MAGNETOCAPACITANCE

The magnetocapacitance between a two-dimensional electron system (2DES ) and the gate electrode on it has been measured in the fractional qua ntum Hall effect regime. By measuring the edge-length dependence of th r magnetocapacitance, we show that the conducting region (the edge sta te) is formed along the sample boundary. The width of edge state ((W-e )) and the bulk conductivity of the 2DES are estimated from the freque ncy dependence of the magnetocapacitance. The estimated W-e is much wi der than that expected from the one-electron approximation picture in the integer quantum Hall regime. [S0031-9007(98)07725-4].