Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 66: Topological Insulators (Joint session of DS, HL, O, and TT, organized by MA)

HL 66.10: Vortrag

Mittwoch, 9. März 2016, 17:30–17:45, H32

Effective geometric phases and topological transitions in SO(3) and SU(2) rotations — •Henri Saarikoski¹, J. Enrique Vázquez-Lozano², José Pablo Baltanás², Junsaku Nitta³, and Diego Frustaglia² — ¹RIKEN Center for Emergent Matter Science, Japan — ²Departamento de Física Aplicada II, Universidad de Sevilla, Spain — ³Department of Materials Science, Tohoku University, Japan

We address the development of geometric phases in classical and quantum magnetic moments (spin-1/2) precessing in an external magnetic field. We show that nonadiabatic dynamics lead to a topological phase transition determined by a change in the driving field topology. The transition is associated with an effective geometric phase which is identified from the paths of the magnetic moments in a spherical geometry. The topological transition presents close similarities between SO(3) and SU(2) cases but features differences in e.g. the limiting values of the geometric phases [1]. We discuss possible experiments where the effective geometric phase would be observable [2].

[1] H. Saarikoski, J. E. Vázquez-Lozano, J. P. Baltanás, J. Nitta, and D. Frustaglia, arXiv:1511.08315 (2015). [2] H. Saarikoski, J. E. Vázquez-Lozano, J. P. Baltanás, F. Nagasawa, J. Nitta, and D. Frustaglia, Phys. Rev. B 91, 241406(R) (2015).