Interference effects induced by a precessing easy-plane magnet coupled to a helical edge state

authored by: Kevin A. Madsen, Piet W. Brouwer, Patrik Recher, Peter G. Silvestrov
Abstract: The interaction of a magnetic insulator with the helical electronic edge of a two-dimensional topological insulator has been shown to lead to many interesting phenomena. One of these is that for a suitable orientation of the magnetic anisotropy axis, the exchange coupling to an easy-plane magnet has no effect on DC electrical transport through a helical edge, despite the fact that it opens a gap in the spectrum of the helical edge [Meng, Phys. Rev. B 90, 205403 (2014)PRBMDO1098-012110.1103/PhysRevB.90.205403]. Here, we theoretically consider such a magnet embedded in an interferometer, consisting of a pair of helical edge states connected by two tunneling contacts, at which electrons can tunnel between the two edges. Using a scattering matrix approach, we show that the presence of the magnet in one of the interferometer arms gives rise to AC currents in response to an applied DC voltage. On the other hand, the DC Aharonov-Bohm effect is absent at zero temperature and small DC voltages, and only appears if the applied voltage or the temperature exceeds the magnet-induced excitation gap.
External Organisation(s): Freie Universität Berlin (FU Berlin)
Technische Universität Braunschweig
Laboratory for Emerging Nanometrology Braunschweig (LENA)
Type: Article
Journal: Physical Review B
Volume: 103
ISSN: 2469-9950
Publication date: 24.03.2021
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Condensed Matter Physics
Electronic version(s): https://doi.org/10.1103/PhysRevB.103.115142 (Access: Unknown)

BibTeX

@article{911da22ae4b649d4a7beea83fc173399,
title = "Interference effects induced by a precessing easy-plane magnet coupled to a helical edge state",
abstract = "The interaction of a magnetic insulator with the helical electronic edge of a two-dimensional topological insulator has been shown to lead to many interesting phenomena. One of these is that for a suitable orientation of the magnetic anisotropy axis, the exchange coupling to an easy-plane magnet has no effect on DC electrical transport through a helical edge, despite the fact that it opens a gap in the spectrum of the helical edge [Meng, Phys. Rev. B 90, 205403 (2014)PRBMDO1098-012110.1103/PhysRevB.90.205403]. Here, we theoretically consider such a magnet embedded in an interferometer, consisting of a pair of helical edge states connected by two tunneling contacts, at which electrons can tunnel between the two edges. Using a scattering matrix approach, we show that the presence of the magnet in one of the interferometer arms gives rise to AC currents in response to an applied DC voltage. On the other hand, the DC Aharonov-Bohm effect is absent at zero temperature and small DC voltages, and only appears if the applied voltage or the temperature exceeds the magnet-induced excitation gap.",
author = "Madsen, {Kevin A.} and Brouwer, {Piet W.} and Patrik Recher and Silvestrov, {Peter G.}",
note = "Funding information: P.R. thanks Adrian Schneider for insightful discussions in an early stage of the project. We acknowledge financial support by the German Science Foundation (DFG) through Grants No. RE 2978/8-1 (P.S., P.R.) and No. BR 7074/4-1 (P.W.B.) and by project A02 of the CRC-TR 183 “entangled states of matter” (P.W.B., K.M.). P.R. and P.S. further acknowledge support from the DFG under Germany's Excellence Strategy, EXC-2123 QuantumFrontiers, 390837967.",
year = "2021",
month = mar,
day = "24",
doi = "10.1103/PhysRevB.103.115142",
language = "English",
volume = "103",
journal = "Physical Review B",
issn = "2469-9950",
publisher = "American Institute of Physics",
number = "11",
}