Experimental realization of a Fabry-Perot-type interferometer by co-propagating edge states in the integer and fractional quantum Hall effect regimes

Abstract

ABSTRACT A Fabry-Perot-typeinterferometer is experimentally realized for electrons in a semiconductor device. Interferenceconditions are created for co-propagat ing electrons in quantum Hall edge states, which results in oscillations ofthe current through the device for integer and fractional “lling factors. We “nd the interference oscillationsin transport across the incompressible strips with local “lling factors c =1,4/3,2/3evenathighimbalances,exceeding the spectral gaps. In contrast , there is no sign of the interferenc e in transport across the principalLaughlin c =1/3 incompressible strip. This indicates, that even at fractional c , the interference eects arecaused by ŽnormalŽ electrons. The oscillations period is determined by the eective interferometer area, whichis sensitive to the “lling factors because of screening eects.Keywords: Quantum Hall eect, interference, qu antum interferometer, edge states 1. INTRODUCTION Interference phenomena in semiconductors have recently attracted considerable interest.