Two-dimensional oxides assembled by M_{4} clusters (M=B, Al, Ga, In, Cr, Mo, and Te)

Abstract

Cluster-assembled materials have long been pursued as they provide unprecedented opportunities to integrate desired functionalities in technological devices. However, patterning clusters in ordered phases in avoid of agglomeration remains challenging. Here we propose a strategy to construct stable two-dimensional (2D) superlattices by using tetrahedral clusters covalently linked by oxygen atoms. When satisfying the closed shells of both molecular and atomic orbitals for the clusters and oxygen linkers, respectively, the assembled 2D superlattices exhibit outstanding energetic, dynamic, and thermal stabilities. Following these criteria, monolayers of B_{4}O_{2}, Al_{4}O_{2}, Ga_{4}O_{2}, In_{4}O_{2}, Cr_{4}O_{2}, Mo_{4}O_{2}, and Te_{4}O_{2} were assembled, which possess application-desired physical properties, such as moderate band gaps, small carrier effective masses, and strong optical absorption in the visible regime. These critical insights pave a new avenue to fabricate new materials and devices using cluster building blocks with precise structures and functionalities.