Robust Majorana modes in one-dimensional disordered binary alloy

Abstract

The one-dimensional (1D) Aubry-Andree-Harper (AAH) model shows some unique electronic and topological features. It is well known that the diagonal AAH model shows a localization transition at a critical strength of the disorder. On the other hand, recently it has been shown that the off-diagonal AAH model has topologically protected degenerate Majorana modes. It was also shown that to lift this degeneracy one need to introduce cosine modulated diagonal potential term and next nearest neighbor hopping with several adjustable parameters. In this work, we show that similar results can be achieved simply by implementing the off-diagonal AAH model on a binary alloy in 1D. This is a much simpler model which will be easier to implement in an optical lattice experiment. We further show that the Majorana modes remain robust even when the underlying binary lattice is disordered.