Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 52: Transport: Spintronics, Magnetotransport 1 (jointly with HL and MA)
TT 52.3: Vortrag
Donnerstag, 14. März 2013, 10:00–10:15, H18
Aharonov-Casher effect in quantum rings: geometric phase shift by in-plane magnetic field — Diego Frustaglia1, •Henri Saarikoski2, Klaus Richter2, Fumiya Nagasawa3, and Junsaku Nitta3 — 1Departamento de Física Aplicada II, Universidad de Sevilla, Sevilla, Spain — 2Department of Theoretical Physics, Regensburg University, Germany — 3Department of Materials Science, Tohoku University, Sendai, Japan
We study transport through Rashba spin-orbit coupled quantum rings where the spin-orbit field causes the Aharonov-Casher effect [1, 2]. The ring is subject to an in-plane magnetic field which gives rise to a shift in the geometric phase. We show that the in-plane field allows control of the geometric phase independently from the dynamic phase and without competing with Aharonov-Bohm phases. We use perturbation theory to calculate the resulting phase shift in quasi-1D rings for weak in-plane fields. The resulting phase shift is quadratic in the in-plane field. Numerical Recursive Green’s function algorithm is used to study the effect in multi-mode quantum rings and in the case of large in-plane fields. We demonstrate the effect in InGaAs/InAlAs based quantum rings where the Rashba spin-orbit field is modulated by an external gate. As the in-plane magnetic field is increased we find a quadratic phase shift in the Aharonov-Casher effect towards lower spin-orbit fields in good agreement with calculations.
[1] F. Nagasawa, J. Takagi, Y. Kunihashi, M. Kohda, and J. Nitta, Phys. Rev. Lett. 108, 086801 (2012)
K. Richter, Physics 5, 22 (2012).