Stripe charge order driven manipulation of Majorana bound states in 2M-WS2 topological superconductor

TL;DR

This study demonstrates that a surface charge stripe order in the topological superconductor 2M-WS2 can be used to controllably manipulate the position of Majorana bound states, which are crucial for topological quantum computing.

Contribution

It reveals how surface charge order coexisting with superconductivity in 2M-WS2 can be used to tune Majorana bound states without destroying the bulk topological properties.

Findings

Stripe order suppresses MBS in vortices under magnetic field.

Charge order shifts MBS away from the surface.

Surface stripe order does not affect bulk topology.

Abstract

Majorana bound states (MBSs) are building blocks for topological quantum computing. They can be generated via the combination of electronic topology and superconductivity. To achieve logic operations via Majorana braiding, positional control of the MBS must be established. To this end, exotic co-existing phases or collective modes in an intrinsic topological superconductor can provide a tuning knob to manipulate the MBS. Here we report the observation of a striped surface charge order coexisting with superconductivity and its controllable tuning of the MBS in the topological superconductor 2M-WS2 using low-temperature scanning tunneling microscopy. By applying an out-of-plane magnetic field, we observe that MBS is absent in vortices in the region with strong stripe order. This is in contrast to adjacent underlaying layers without charge order where vortex-bound MBSs are observed. Via theoretical simulations, we show that the surface stripe order does not destroy the bulk topology, but it can effectively modify the spatial distribution of MBS, i.e., it pushes them downward away from the 2M-WS2 surface. Our findings demonstrate that the interplay of charge order and topological superconductivity can be used to manipulate the positions of the MBS, and to explore of new states of matter.