Ab initio study of the electronic, vibrational, and mechanical properties of the magnesium diboride monolayer

Magnesium diboride gained significant interest in the materials science community after the discovery of its superconductivity, with an unusually high critical temperature of 39 K. Many aspects of the electronic properties and superconductivity of bulk MgB₂ and thin sheets of MgB₂ have been determined; however, a single layer of MgB₂ has not yet been fully theoretically investigated. Here, we present a detailed study of the structural, electronic, vibrational, and elastic properties of monolayer MgB₂, based on ab initio methods. First-principles calculations reveal the importance of reduction of dimensionality on the properties of MgB₂ and thoroughly describe the properties of this novel 2D material. The presence of a negative Poisson ratio, higher density of states at the Fermi level, and a good dynamic stability under strain make the MgB₂ monolayer a prominent material, both for fundamental research and application studies.