Interfacial Conductance Measurements of the 𝜈 = 5/2 Fractional Quantum Hall State

The 𝜈 = 5/2 fractional quantum Hall state is expected to be characterized by non-Abelian braiding statistics. Identification of the underlying topological order in real 2D systems remains an outstanding challenge. Here we report on measurements of interfacial conductance in a GaAs-based device in which regions of filling factor 𝜈 = 2, 5/2, and 𝜈 = 3 are brought into close proximity. Motivated by a theoretical proposal [1], we aim to distinguish between three major candidate states for 𝜈 = 5/2: the Moore-Read Pfaffian (MR-Pf), its particle-hole conjugate, the anti-Pfaffian (aPf) and the particle-hole invariant Pfaffian (PH-Pf). Our device architecture is built on an ultra-high-quality GaAs heterostructure to interface a large gap 𝜈 = 5/2 state with adjacent regions in which the filling factor is set to 𝜈 = 2 and 𝜈 = 3. We have measured the conductance along these interfaces while varying the interface length from 20μm to 1μm in devices employing distinct geometries. A principal focus of our work is to understand the length and temperature scales that separate coherent from incoherent edge mode transport at 𝜈 = 5/2. Preliminary results along with comparison to existing models of edge structure at 𝜈 = 5/2 will be presented.

[1]. M. Yutushui, A. Stern, D. F. Mross, Phys. Rev. Lett. 128, 016401 (2022)