CuB monolayer: a novel 2D anti-van’t Hoff/Le Bel nanostructure with planar hyper-coordinate boron/copper and superconductivity

Abstract

To achieve specific applications, it is always desirable to design new materials with peculiar topological properties. Herein, based on a D2h B2Cu6H6 molecule with the unique chemical bonding of planar pentacoordinate boron (ppB) as a building block, we constructed an infinite CuB monolayer by linking B2Cu6 subunits in an orthorhombic lattice. The planarity of the CuB sheet is attributed to the multicenter bonds and electron donation-back donation, as revealed by chemical bonding analysis. As a global minimum confirmed by the particle swarm optimization method, the CuB monolayer is expected to be highly stable, as indicated by its rather high cohesive energy, absence of soft phonon modes, and good resistance to high temperature, and thus is highly feasible for experimental realization. Remarkably, this CuB monolayer is metallic and predicted to be superconducting with an estimated critical temperature (Tc) of 4.6 K, and the critical temperature could be further enhanced by tensile strains (to 21 K at atmospheric pressure).

Two-dimensional Be2Al and Be2Ga monolayer: anti-van’t Hoff/Le Bel planar hexacoordinate bonding and superconductivity

“…58 In 2016, the FeB 2 monolayer was characterized as a boron-based Dirac material with a Dirac state in the Fermi level of its band structure. 47 Recently, Be 2 Au 59 and CuB 60 monolayers were confirmed as phonon-mediated intrinsic superconductors, where the former is a rare Dirac material with two perfect Dirac node-loops in its band structure. The stable FeSi 2 was also recently found to be an intriguing 2D ferromagnet.…”