Global minimum and new metastable atomic structures of metal clusters

The evolutionary algorithm coupled with density functional (DFT) method is used to identify the global energy minimum and the metastable atomic structures of metal clusters, as implemented in USPEX, we studied the atomic structure, binding energies, effective coordination numbers, average bond lengths, and magnetic properties of 13-atom Cu, Co and Cr clusters. A set of metastable and global minimum atomic structures as supported by vibrational analysis are identified. Global energy metastable configurations are identified for 13- atom Cu, Co and Cr clusters and previous known global minimum atomic structures were confirmed by our calculations. We found that the Cu₁₃ cluster has a distorted hexagonal bilayer (HBL)-like structure, which is composed by two layers as in the ideal HBL structure. The distorted HBL Cu₁₃ is 1.09 eV lower in total energy compared to close-packed icosahedral (ICO) configuration. Our calculations show that Co₁₃ has an ideal HBL structure and Cr₁₃ cluster has distorted ICO structure. Moreover, our calculations show that Cr₁₃ has another lower energy atomic configuration with 0.13 eV difference form ICO. Cr₁₃ has ferrimagnetic (FIM) interaction which plays an important role in finding the lowest energy structure.