Device platform for high precision measurement of chemical potential in fractional quantum Hall states

Thermodynamic properties such as entropy may provide insight into topological properties of strongly interacting electron states. We report on the design, fabrication, and operation of devices in AlGaAs/GaAs heterostructures designed to facilitate high precision measurements of chemical potential in the fractional quantum Hall regime. Measurement of chemical potential concurrently with electron temperature extraction allows for the determination of entropy. An excess entropy is theorized to be associated with the topological degeneracy of the ground state at the ν = 5/2 FQH state, which is believed to host non-abelian anyons. The unique non-abelian anyon entropy signature can be extracted from the measured temperature dependence of chemical potential. Our heterostructure and device design are adaptable to several modes of chemical potential measurement. We discuss measurements in distinct modes of operation to determine sensitivity limits. Preliminary experiments at ν = 5/2 are presented.