Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 4: Physics of quantum rings (Focus session with TT)

HL 4.1: Topical Talk

Monday, March 31, 2014, 09:30–10:00, POT 151

Impact of topology on physical properties of quantum rings — •Vladimir M. Fomin — Institute for Integrative Nanosciences, IFW-Dresden, Helmholtzstraße 20, 01069 Dresden, Germany

Advanced micro- and nanostructure fabrication techniques can be exploited to generate non-trivially shaped objects possessing man-designed topological features, such as doubly-connectedness (quantum rings) and one-sidedness (Möbius strips) [1]. Even though self-assembled semiconductor quantum rings (‘quantum volcanos’) are singly-connected and anisotropic, they exhibit the Aharonov-Bohm effect on the persistent current because the electron wave functions are exponentially decaying towards the center and are topologically identical to those in doubly-connected quantum rings. Theoretically predicted Aharonov-Bohm effect in ‘quantum volcanos’ was experimentally detected by torsion magnetometry. Symbiosis of a geometric potential and an inhomogeneous twist renders an observation of the topology effect on the electron ground-state energy in microscale Möbius strips into the realm of experimental verification. A ‘delocalization-to-localization’ transition for the electron ground state is unveiled in inhomogeneous Möbius strips [2]. This transition can be quantified through the Aharonov-Bohm effect on the persistent current. Recent findings suggest perspectives of topological control over electronic, spin, optical, magnetic and transport properties of micro- and nanostructures.

[1] V. M. Fomin (Ed.), Physics of Quantum Rings, Springer, Berlin–Heidelberg, 2014, 487 p. XX [2] V. M. Fomin, S. Kiravittaya, O. G. Schmidt, Phys. Rev. B 86, 195421 (2012).