TOPOLOGY- AND GEOMETRY-DRIVEN PROPERTIES OF ADVANCED NANOARCHITECTURES

by Prof. V. M. Fomin (Leibniz IFW Dresden and Moldova State University)

Friday 14 Jun 2019, 11:00 → 12:00 Europe/Rome

Seminar Room PT (NEST)

Study of topological matter is one of the fascinating main roads of modern physics. The realm of topological matter can be conventionally subdivided into two categories. First, non-trivial topology occurs due to a special geometry of structures or fields in real space, e.g., quantum rings [1] and Skyrmions. The second category embraces various topologically protected edge states governed by Dirac physics and/or topologically non-trivial electronic structure in the reciprocal space. Self-organization techniques allow for fabrication of micro- and nano-architectures of different materials: semiconductors, superconductors, dielectrics. I will represent the fundamental electronic, photonic and phononic effects exercised by topological mechanisms owing to complex geometries of those nanoarchitectures [2, 3]. A novel insight is being achieved by extending the paradigm of topology-driven properties from quantum rings onto a broaderclass of doubly-connected nanoarchitectures. Core–multishell GaAs/AlAs nanowires are shown to be an excellent platform for investigations of the Aharonov–Bohm effect of neutral and charged excitons. Owing to the atomically flat interfaces and the absence of alloy disorder, excitonic phase coherence is clearly demonstrated through observation of the Aharonov-Bohm oscillations in the photoluminescence spectra even in quantum rings with circumferences as large as 200 nm [4]. Rolling up superconductor Nb nanomembranes into open tubes allows for a new, highly correlated vortex dynamics regime that can be detected through the induced voltage and leads to their application as tunable superconducting flux generators for fluxon-based information technologies [5]. Resonant Terahertz light absorption can be enhanced by virtue of hybrid interface phonon–plasmon modes in semiconductor nanoshell quantum dots, which are tunable through the electron doping of the semiconductor core or shell [6]. 

1. V. M. Fomin (Ed.), Physics of Quantum Rings, 2nd Edition, (Cham: Springer International Publishing, 2018). 
2. V. M. Fomin, Topology-driven effects in advanced nanoarchitectures, in: A. Sidorenko (Ed.), Functional Nanostructures and Metamaterials, (Cham: Springer International Publishing, 2018). 
3. V. M. Fomin, Topology and Geometry Controlled Properties of Nanoarchitectures, Phys. Stat. Sol. – RRL. Vol. 13, 1800595 (2019). 
4. P. Corfdir, O. Marquardt, R. B. Lewis, C. Sinito, M. Ramsteiner, A. Trampert, U. Jahn, L. Geelhaar, O. Brandt, V. M. Fomin, Adv. Mater. 31, 1805645 (2019) 
5. R. O. Rezaev, E. A. Posenitskiy, E. I. Smirnova, E. A. Levchenko, O. G. Schmidt, V. M. Fomin, Phys. Stat. Sol. – RRL, 13, 1800251 (2019). 
6. D. L. Nika, E. P. Pokatilov, V. M. Fomin, J. T. Devreese, J. Tempere, Applied Sciences 9, 1442 (2019).