Quantum Hall Interferometry in Graphene

Electrons in two dimensions can exhibit unique correlated phenomena such as the fractional quantum Hall effect under strong magnetic fields, in which excitations of composite fermions are fractionally charged. These excitations are predicted to be neither fermionic nor bosonic, but rather should exhibit anyonic exchange statistics in which the wave function acquires a complex phase upon exchange of two identical quasiparticles. However, so far there has been no direct confirmation of these anyonic exchange statistics due to numerous challenges performing the necessary braiding operations in high-mobility 2DEGs. Here, we develop Mach-Zehnder and Fabry-Pérot interferometers in ultra-high quality graphene devices operated in the fractional quantum Hall regime in order to test these predictions. Our efforts to achieve this utilize a variety of device geometries, primarily focused on the use of pn junctions or electrostatically-defined quantum point contacts in graphene.