Sublattice-sensitive Majorana Modes

TL;DR

This paper demonstrates that sublattice-dependent boundary properties in topological insulators enable the realization and precise manipulation of Majorana modes at boundary domain walls, opening new avenues for topological quantum computation.

Contribution

It introduces a general theory showing how sublattice-sensitive boundary terminations can host and control Majorana modes in topological insulators.

Findings

Majorana modes can be realized at sublattice domain walls.

Their positions can be precisely manipulated via boundary control.

Sublattice degrees of freedom offer new routes for Majorana mode engineering.

Abstract

For two- and three-dimensional topological insulators whose unit cells consist of multiple sublattices, the boundary terminating at which type of sublattice can affect the time-reversal invariant momentum at which the Dirac points of helical boundary states are located. Through a general theory and a representative model, we reveal that this interesting property allows the realization of Majorana modes at sublattice domain walls forming on the boundary when the boundary Dirac points of the topological insulator are gapped by an unconventional superconductor in proximity. Intriguingly, we find that the sensitive sublattice-dependence of the Majorana modes allows their positions to be precisely manipulated by locally controlling the terminating sublattices or boundary potential. Our work reveals that the common sublattice degrees of freedom in materials open a new route to realize and manipulate Majorana modes.