Probing long-range current-carrying edge modes by two quantum pointcontacts

• Published in: Low temperature physics (Woodbury, N.Y.) N.Y.), 2021-12, Vol.47 (12)
• Main Authors: Belogolovskii, M, Zhitlukhina, E, Seidel, P
• Format: Article
• Language: English
• Subjects: Differential geometry; Elementary excitations; Low temperature; Magnetic fields; Magnetism; Tips; Wave functions
• ISSN: 1063-777X; 1090-6517

The origin of anomalous current-carrying edge states in quasi-two-dimensional quantumsamples with an insulating interior is currently mysterious. We propose to address thisissue using a hybrid setup, an interferometric phase-sensitive configuration of twoindependent scanning probe tips, normal and superconducting, able to realize the quantuminterference effect of quasiparticle currents moving in different directions along themetallic-like one-dimensional near-boundary channels. To simulate the dissipationless edgecurrents, we consider a quantum material with a simple Corbino disk geometry and analyzehow 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 differencebetween classical and quantum expectations should clarify the enigmatic origin of thelong-range conducting modes observed in different materials at low temperatures. Strongdependence on the applied magnetic field can be useful for practical implementation of thequantum effects associated with the phase difference of electron wave functions in thering geometry.