Impurity-mediated early condensation of an atomic layer electronic crystal

TL;DR

This study reveals how impurity atoms induce local charge density wave condensation in atomic wires through cooperative lattice strain, providing insights into impurity effects on electronic phase transitions at atomic scales.

Contribution

It uncovers the atomistic mechanism of impurity-induced CDW condensation involving cooperative lattice strain, advancing understanding of impurity effects on electronic phases.

Findings

Impurity atoms induce local CDW condensation above transition temperature.

Multiple impurities cooperate to induce CDW along atomic wires.

First principles calculations reveal the role of lattice strain in the mechanism.

Abstract

While impurity has been known widely to affect phase transitions, the atomistic mechanisms have rarely been disclosed. We directly show in atomic scale how impurity atoms induces the condensation of a representative electronic phase, charge density wave (CDW), with scanning tunneling microscopy. Oxygen impurity atoms on the self-assembled metallic atomic wire array on a silicon crystal condense CDW locally even above the transition temperature, More interestingly, the CDW along the wires is induced not by a single atomic impurity but by the cooperation of multiple impurities. First principles calculations disclose the mechanism of the cooperation as the coherent superposition of the local lattice strain induced by impurities, stressing the coupled electronic and lattice degrees of freedom for CDW. This newly discovered mechanism can widely be applied to various important electronic orders coupled to lattice, opening the possibility of the atomic scale strain engineering.