The structural arrangement of noble metal atoms, for example, in clusters, can influence their physical and chemical properties. Converting bulk metals or 2D nanostructures from, e.g., a hexagonal lattice to a cluster-packed structure could, thus, be interesting for tuning their properties for applications.

Kui Du, Shenyang National Laboratory for Materials Science, Chinese Academy of Sciences, and colleagues have found that gold nanoribbons with a hexagonal lattice can be converted to nanoribbons packed mostly from heptagonal clusters. The structural transition was induced by mechanical tension and observed using aberration-corrected high-resolution transmission electron microscopy (AC-HRTEM). Some of the heptagonal clusters in the resulting material are edge-connected. Under compression, the structural change can be reverted, leading back to a hexagonal lattice.

The phase transitions change the properties of the nanoribbons: For example, the electrical conductances in the hexagonal lattice nanoribbon and the heptagonal-cluster-packed nanoribbon are different. Thus, the conductance can be switched using external strain, which might be useful for applications.

• Phase Transition to Heptagonal-Cluster-Packed Structure of Gold Nanoribbons,
  Chunjin Chen, Kepeng Song, Xuelu Wang, Kui Du,
  J. Am. Chem. Soc. 2022.
  https://doi.org/10.1021/jacs.1c12713