Electric-field control of zero-dimensional topological states in ultranarrow germanene nanoribbons

TL;DR

This paper demonstrates reversible electric-field control of zero-dimensional topological states in ultranarrow germanene nanoribbons, enabling potential applications in quantum memory and neuromorphic computing.

Contribution

It introduces an atomic-scale platform for switching topological end states on and off using electric fields in germanene nanoribbons, a novel approach for topological device control.

Findings

Electric field switches topological end states in germanene nanoribbons.

Ultranarrow ribbons exhibit controllable zero-dimensional states.

Proof-of-principle for a topological field effect device.

Abstract

Reversible, all-electric control of symmetry-protected zero-dimensional modes has been a long-standing goal. In buckled honeycomb lattices, a perpendicular field couples to the staggered sublattice potential providing the required handle. We combine scanning tunneling microscopy and tight-binding theory to switch zero-dimensional topological end states reversibly on and off in ultranarrow germanene nanoribbons by tuning the electric field in the tunnel junction. Increasing the field switches off the end modes of topological two-hexagon wide ribbons, while the same field switches on zero-dimensional states in initially trivial three- and four-hexagon wide ribbons. This atomic scale platform realizes a proof-of-principle for a zero-dimensional topological field effect device, opening a path for ultrasmall memory, controllable qubits, and neuromorphic architectures.