Searching for cluster Lego blocks for three-dimensional and two-dimensional assemblies
Qiuying Du, Zhen Wang, Si Zhou, Jijun Zhao, Vijay Kumar
Abstract
Assemblies of clusters have been sought for a long time to synthesize new materials with unprecedented physical phenomena or to integrate desired functionalities for technological applications. However, except for some carbon fullerenes and ligated clusters, little progress has been made in achieving assemblies of other clusters due to their tendency for agglomeration. Here we study interaction in dimers of 34 well-studied endohedrally doped clusters (i.e., superatoms) and propose the criteria for such superatoms to be potential building blocks in terms of surface coordination, charge state, distribution of the highest occupied molecular orbital, and electronic as well as atomic shell (double-shell) closure. From these results, the endohedrally doped $\mathrm{Ti}@{\mathrm{Ge}}_{16}$ cage cluster stands out as a suitable building block to assemble solids and nanostructures with outstanding stabilities and diverse physical properties. We report here the finding of antiferromagnetic Mott insulator in metal intercalated two-dimensional crystal of such cluster. Our study provides essential knowledge for achieving stable cluster assemblies of different dimensionalities with precisely tailorable electronic structure for device applications.