Creation and annihilation of mobile fractional solitons in atomic chains

TL;DR

This paper reports the discovery and manipulation of mobile fractional topological solitons in silicon atomic chains, revealing their potential for robust information processing in topological systems.

Contribution

It demonstrates the creation, control, and topological origin of fractionalized solitons in atomic chains, a novel platform for topological quantum states.

Findings

Identification of phase defects with fractional charges of ±2e/3 and ±4e/3

Observation of defect motion activated above 100 K

Ability to create and annihilate solitons at specific locations

Abstract

Localized modes in one dimensional topological systems, such as Majonara modes in topological superconductors, are promising platforms for robust information processing. In one dimensional topological insulators, mobile topological solitons are expected but have not been fully realized yet. We discover fractionalized phase defects moving along trimer silicon atomic chains formed along step edges of a vicinal silicon surface. Tunneling microscopy identifies local defects with phase shifts of 2{\pi}/3 and 4{\pi}/3 with their electronic states within the band gap and with their motions activated above 100 K. Theoretical calculations reveal the topological soliton origin of the phase defects with fractional charges of {\pm}2e/3 and {\pm}4e/3. An individual soliton can be created and annihilated at a desired location by current pulse from the probe tip. Mobile and manipulatable topological solitons discovered here provide a new platform of robustly-protected informatics with extraordinary functionalities.