Wydarzenia w AGH

Wykład zatytułowany One and Two Dimensional Topological Superconductivity wygłosi dr hab. Nicholas Sedlmayr, prof. UMCS (Uniwersytet im. Maria Curie-Skłodowskiej w Lublinie, Instytut Fizyki).

Udział

• stacjonarny: ACMiN (ul. Kawiory 30, bud. D-16, II piętro, sala audytoryjna 1.02A)
• zdalny: platforma MS Teams (link)

Streszczenie

Here we will offer a variety of different models and directions for creating two dimensional (and quasi-one dimensional) topological superconductors. We begin by revisiting the problem of Majorana zero modes in chains of scalar impurities deposited on a superconductor with a mixed s-wave and p-wave pairing. We find that the magnetic impurity chains exhibit well localised Majorana states when the substrate is trivial, but these states hybridise and get dissolved in the bulk when the substrate is topological. In analysing this system we make use of the Majorana polarisation, a technique for investigating Majorana zero modes. We will show how this can be (partly) measured, which will help us in investigating which kinds of Majorana can exist on the edges of two dimensional topological superconductors with chiral edge modes. We consider also a dual proximity effect between topological insulators and superconductors. Furthermore two dimensional topological superconductors with chiral edge modes are predicted to possess a quantised thermal Hall effect proportional to the Chern number, exactly half that for chiral topological insulators. Here we introduce a model based on a proximity induced superconducting bismuth bilayer and directly calculate the thermal Hall conductance of this lattice model. We demonstrate the quantised thermal Hall plateaus in several different topological phases and compare this to numerical calculations of the Chern number, as well as analytical calculations of the Chern number's parity invariant. We demonstrate that it is possible to get a reasonable topological phase diagram from the quantised thermal Hall calculations.