Consideration of ac Josephson Effect in Fractional Quantum Hall States

Shosuke Sasaki

Published 2008-07-02Version 1

The ac Josephson effect phenomenon is studied in fractional quantum Hall states (FQHS). Usual quantum Hall devices have an electron layer of uniform thickness. We consider a new quantum Hall device. The device has a narrow part that is vertical to the direction of the current. The narrow part has a smaller electron layer thickness than in the other part. The ac Josephson effect might be observed when the magnetic field or the electric current is modulated by an oscillation with a constant frequency value f. Steps of the voltage appear when an electric current exceed a threshold value. The step value V is related to the transfer charge Q as V=(2 pi hbar f)/Q. We examine how the value of the transfer charge Q depends on the fractional filling factor nu. The nu - dependence of Q is affected by the wave function of the fractional quantum Hall state. We classify the value of Q according to the wave function type. Accordingly, observation of the ac Josephson effect in FQHS clarifies the structure of the fractional quantum Hall states.