Preliminary Results of Interference Experiments in the Second Landau Level

Abstract

Possible ways to implement a Fabry-Pérot interferometer for the investigation of the properties of the $\nu$ = 5/2 state are discussed. Defining structures on top of high mobility heterostructures is an experimental challenge and requires detailed study. The geometry of an interferometer has to be carefully chosen in order to be able to perform the envisioned experiments. In the present chapter, we give an overview of progress that we have made towards such an interference experiment at $\nu$ = 5/2. We present magnetotransport measurements of three different samples, based on heterostructures fabricated with different growth and doping techniques. Experimental challenges that arise and possible solutions are addressed. We demonstrate how a top-gate defined interferometer can be defined, transmitting a fully gapped $\nu$ = 5/2 FQH state with an energy gap exceeding 200 mK.