Physics (Internal)

Zero-energy states in two-dimensional superconductors: Creating a chain of Majorana fermions

This event is part of the Condensed Matter Theory Seminar Series.

Abstract: Majorana fermions were originally proposed as a model for
neutrinos in high-energy physics and have the defining property that they are their own anti-particles. Partly because of its potential application to topological quantum computation, this concept has attracted revived interest in the form of certain many-body states in condensed-matter physics. I will discuss how Majorana states emerge in two different two-dimensional systems: as zero-energy states bound to vortices at superconducting interfaces which lack inversion symmetry and in vortices of superconducting surface states of three-dimensional topological insulators. The specific properties of these systems will then be used to propose a heterostructure that can host a chain of equally spaced vortices in the superconducting order parameter, each of which binds a Majorana state. It turns out that the overlap integral of neighboring Majorana states can be controlled by the position of the chemical potential. Equipped with this property, such a heterostructure could in principle serve as a one-dimensional circuit path for Majorana fermions.