Ali Yazdani

Majorana in Chains and Hinges

In recent years, following pioneeringtheoretical work of Kitaev and others, we have learned how to engineermaterials that harbor quasiparticles that behave similar to fermions thatMajorana had first envisioned. In particular, there has been a focus onone-dimensional topological superconductor that harbor Majorana zero modes(MZM) that can potentially be used to make fault-tolerant topological quantumcomputation possible. We have proposed and implemented a platform forrealization of topological superconductivity and MZM in chains of magneticatoms on the surface of a superconductor. In this talk, I will review theseries of experiments on this platform that we have performed to establish thepresence of these exotic quasi-particle using spectroscopic mapping with thescanning tunneling microscope (STM). These include the most recent study of theunique spin signature of MZM. I focus most of the talk on a new platform wherewe use the one-dimensional helical hinge states of a higher order topologicalinsulators. In particular, I will show experiment demonstrating how combinationof magnetism and superconductivity on such one-dimensional states can also giverise to MZM that can be detected with an STM. Overall these experiments,illustrate how the power of spectroscopic imaging with the STM can be used tocharacterize novel quantum states of matter and visualize their exotic quasi-particles.