title: Andreev reflection at high magnetic fields: evidence for electron and hole transport in edge states.
abstract: We have studied magnetotransport in arrays of niobium filled grooves in an InAs/Al(x)Ga(1-x)Sb heterostructure. The critical field of up to 2.6 T permits one to enter the quantum Hall regime. In the superconducting state, we observe strong magnetoresistance oscillations, whose amplitude exceeds the Shubnikov-de Haas oscillations by a factor of about 2, when normalized to the background. Additionally, we find that above a geometry-dependent magnetic field value the sample in the superconducting state has a higher longitudinal resistance than in the normal state. Both observations can be explained with edge channels populated with electrons and Andreev-reflected holes.
authors.affiliation: Universität Regensburg, Institut für Experimentelle und Angewandte Physik, Regensburg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Eroms
authors.forename: D
authors.initials: D
authors.lastname: Weiss
authors.forename: J
authors.initials: J
authors.lastname: De Boeck
authors.forename: G
authors.initials: G
authors.lastname: Borghs
authors.forename: U
authors.initials: U
authors.lastname: Zülicke