Physics Colloquium
Synthesizing and visualizing Majorana modes
Dr. Ilya K. Drozdov
Assistant Scientist at the Condensed Matter Physics and Materials Science Division
Brookhaven National Laboratory
In this talk, I will give an introduction to topological phases of matter, topological superconductivity, and, more specifically, excitations of a topological superconductor known as Majorana modes. I will discuss experimental progress in realizing topological phases in materials and observing spectroscopic signatures of those phases with the focus on scanning tunneling microscopy (STM) experiments. One example of such behavior is found in elemental Bismuth, a material that attracted a lot of attention due
to the presence of robust, dispersing, and coherent 1D edge states [1] and possible realization of higher order topology (HOTI) in a material system [2]. Another example of topological behavior is found in superconductors where the edge excitations – Majorana bound states – could possibly demonstrate non-Abelian statistics and are highly sought after for applications in topological quantum computing. I will introduce the platform of magnetic atoms epitaxially deposited on a superconductor [3] and discuss different STM experiments (including spin-polarized STM, and ultra-low-temperature STM spectroscopy) carried out on the system of Fe chains on Pb surface to probe the nature of the observed states and to set experimental bounds on the Majorana interpretation. I will also discuss a more recent experimental platform combining Bismuth and high-Tc into a novel synthetic heterostructure using advanced oxide molecular beam epitaxy. [3]
[1] Drozdov et al., Nature Physics (2014), 10.1038/NPHYS3048
[2] Schindler et al., Nature Physics (2018), 10.1038/s41567-018-0224-7
[3] Nadj-Perge et al., Science (2014), 10.1126/science.1259327
[4] Kundu et al., Advanced Quantum Technologies (2020), 10.1002/qute.202000038
Hosted by Prof. Janko
All interested persons are invited to attend remotely—email physics@nd.edu for information.