Atypical edge current interference in high quality 2D electron systems: both Ising and Fibonacci anyons?*

In the highest quality 2D heterostructures produced to date Fabry-Perot interferometry has shown elaborate oscillation sets at 7/2 and 5/2 consistent in detail with non-Abelian properties expected for Ising anyons. The foundation of these results are the interference periods, consistent with addition of two e/4 charges on B-field sweep and respectfully corresponding to addition of 1/7 and 1/5 of a single flux to the interferometer: the even-odd effect. These oscillations are striking in their stability, amplitude, and packet form. Even more striking are oscillations that occur centered around 12/5 and 17/5, candidate filling factors for Fibonacci anyons. These oscillations are of comparable or even greater amplitude than those at 7/2 and 5/2, are equally stable in time and B-field sweeps, but have more elaborate packet formation: 12/5 and 17/5 oscillations display distinct multiple frequency spectral peaks. Importantly, these spectra have central frequencies corresponding roughly to addition of three e/5 quasiparticles for both 12/5 and 17/5. Presented here will be B-field sweep resistance measurements across the interferometers in different devices and samples with focus on the oscillation features and periods, comparison to other oscillation measurements from filling factors 2 to 4, and exhibited induced phase shifts of 1/3 period. While these particular results show potential consistency with non-Abelian Fibonacci anyons, alternative explanations are presently under study.