MATERIALS SCIENCE SEMINAR

ABSTRACT: I will present recent work on a two-legged spin-chain version of Kitaev's honeycomb model. Like its parent, this model maps to a p-wave superconductor with a topological phase hosting Majorana fermions. The spin system exhibits Z2 vortices which control the sign of a local chemical potential in the fermionic language. I will show that the existence of Majorana fermions can be inferred from a new topological invariant based on a transfer matrix approach. Interestingly, different vortex patterns lead to a diverse set of topological phase diagrams. The results of this work suggest that periodic potentials may be used to `tune' the topology of a 1D superconducting system -- an observation relevant to current proposals to realize Majorana fermions in quantum wires. Our approach offers insight into general features of the topological phase diagram of 1D p-wave superconductors including those with disorder.