Interference properties of charges at filling factor 5/2

ORAL

Abstract

Excitations of charge e/4 at 5/2 filling factor are proposed to obey non-Abelian statistics, and we perform experiments with interferometers operated at fractional quantum Hall states to test this. The interferometers allow variation in the number of flux and quasiparticles encircled by one of the two edge paths that interfere, with those numbers dictating the interference properties. Our recent focus has been on expanding control of those enclosed flux and quasiparticle numbers, and examining the difference in interference presumably due to edge charge e/4 and edge charge e/2 encircling the enclosed area. We observe the expected interference periods corresponding to these quasiparticle charges, displayed in simple magnetic field sweep measurements, but also observe an important difference in the relative magnitudes of the e/4 versus e/2 edge generated interference. For interference to occur the encircling charge must backscatter at the narrowings that define the interference device. As the size of these narrowings is changed the magnitude of the e/2 interference is observed to be sensitive to this size, while the e/4 interference is relatively insensitive, as expected in theoretical models. We review this data taken in multiple heterostructures and device designs.

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Presenters

  • Robert Willett

    Nokia Bell Labs, Nokia - Bell Labs

Authors

  • Robert Willett

    Nokia Bell Labs, Nokia - Bell Labs

  • Michael Manfra

    Department of Physics and Astronomy and Station Q Purdue, Purdue University, Department of Physics and Astronomy and Microsoft Station Q Purdue, Purdue University, Purdue University, Physics, Purdue University, Purdue University, Station Q Purdue, Purdue Univ, Department of Physics and Astronomy, and School of Materials Engineering, and School of Electrical and Computer Engineering, Purdue University, Physics and Astronomy, Purdue University, Dept. of Physics and Astronomy, Purdue Univ

  • Loren Pfeiffer

    Electrical Engineering, princeton university, Department of Electrical Engineering, Princeton University, Princeton University, Princeton Univ, Electrical Engineering, Princeton Univ, EE, Princeton University