Fizika Nizkikh Temperatur: Volume 47, Number 12 (December 2021), p. 1090-1095 ( to contents , go back )
Probing long-range current-carrying edge modes by two quantum point contacts
M. Belogolovskii and E. Zhitlukhina
Donetsk Institute for Physics and Engineering named after O. O. Galkin of NAS of Ukraine, Kyiv 03028, Ukraine
Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Jena 07743, Germany
Received July 8, 2021, published online October 25, 2021
The origin of anomalous current-carrying edge states in quasi-two-dimensional quantum samples with an insulating interior is currently mysterious. We propose to address this issue using a hybrid setup, an interferometric phase-sensitive configuration of two independent scanning probe tips, normal and superconducting, able to realize the quantum interference effect of quasiparticle currents moving in different directions along the metallic-like one-dimensional near-boundary channels. To simulate the dissipationless edge currents, we consider a quantum material with a simple Corbino disk geometry and analyze how the differential conductance spectrum depends on the distance between the two tips, the applied voltage bias, and the presence of a magnetic field. An essential difference between classical and quantum expectations should clarify the enigmatic origin of the long-range conducting modes observed in different materials at low temperatures. Strong dependence on the applied magnetic field can be useful for practical implementation of the quantum effects associated with the phase difference of electron wave functions in the ring geometry.
Key words: helical edge currents, Corbino disk, two-probe contact setup, differential conductance spectrum.