Atomistic origin of metal versus charge-density-wave phase separation in indium atomic wires on Si(111)

TL;DR

This study reveals how atomic-scale defects in indium atomic wires on Si(111) surfaces influence the formation of metallic and charge-density wave phases, emphasizing the role of defect interactions in electronic phase separation.

Contribution

It uncovers the atomistic mechanisms behind phase separation in In atomic wires, focusing on defect-induced local constraints and interwire interactions.

Findings

Defects flip the CDW phase locally, affecting phase boundaries.

Atomic defects induce local CDW condensates and phase separation.

Defect interactions are crucial for electronic inhomogeneity.

Abstract

We investigate in atomic scale the electronic phase separation occurring in the well known quasi 1D charge-density wave (CDW) phase of the In atomic wire array on a Si(111) surface. The characteristic atomic scale defects, originated from excess In atoms, are found to be actively involved in the formation of the phase boundary between the metallic and the CDW phases by extensive analysis of scanning tunneling microscopy images at various temperatures. These particular defects flip the phase of the quasi 1D CDW to impose strong local constraints in the CDW correlation. We show that such local constraints and the substantial interwire CDW interaction induce local condensates of CDW and the phase separation between the metallic and the CDW phases. This work unveils the atomistic origin of the electronic phase separation, highlighting the importance of atomic scale structures of defects and their collective interaction in electronically inhomogeneous materials.