Seminar

TYC@imperial: Shrinking a topological insulator to nanoscale

Gleb Siroki

Department of Physics, ICL

Monday 20th November 2017
Time: 12.00pm
Venue: Room G01, Royal School of Mines, Imperial College London
Contact: Ms Hafiza Bibi
Tel: 02075947252

Abstract: Band structures are a powerful tool to understand the behaviour of crystalline materials.
This tool is nearly a hundred years old dating back to the discovery of Bloch's theorem. Nevertheless, it keeps providing us with surprises. The last one occured with the recent discovery of topological insulators. This discovery means that all materials with a band gap can be divided into two categories - trivial (ordinary insulators) and topological. The latter host protected edge states at their boundary. These edge states have a peculiar property that left-movers and right-movers have opposite spins. This can be used for spintronics which is a low power successor of electronics we currently rely on. To exploit the  states in practice it is necessary to have the smallest amount of material possible. This is  why studying topological nanoparticles is important. This talk will give a general introduction to the field of topological insulators followed by a discussion of what happens when we shrink a topological insulator to nanoscale (and edge states become more important) [1,2]. Interestingly, topology can be applied to other periodic structures where Bloch theorem applies and the last part of the talk will talk about the analogies with photonic topological insulators [3].

 



[1] Nat. Commun., 7, 12375, August 2016
[2] Physical Review Materials, 1(2), 024201, July 2017.
[3] Physical Review B, 96(4), 041408, July 2017.



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