Formation of copper boride on Cu(111)

TL;DR

This study reports the unexpected formation of an ordered copper boride (Cu8B14) on Cu(111) surfaces under ultrahigh vacuum, revealing complex 2D structures and hybridization phenomena that could enable new low-dimensional materials.

Contribution

It uncovers a novel epitaxial copper boride structure on Cu(111), combining experimental STM data with ab initio predictions to reveal its complex atomic arrangement.

Findings

Discovery of 2D-Cu8B14 structure on Cu(111)

Identification of strong intra-layer p-d hybridization

Observation of significant charge transfer between Cu and B

Abstract

Boron forms compounds with nearly all metals, with notable exception of copper and other group IB and IIB elements. Here, we report an unexpected discovery of ordered copper boride grown epitaxially on Cu(111) under ultrahigh vacuum. Scanning tunneling microscopy experiments combined with ab initio evolutionary structure prediction reveal a remarkably complex structure of 2D-Cu8B14. Strong intra-layer p-d hybridization and a large amount of charge transfer between Cu and B atoms are the key factors for the emergence of copper boride. This makes the discovered material unique and opens up the possibility of synthesizing ordered low-dimensional structures in similar immiscible systems.