Abstract
Nickel diazenide NiN2, is a novel layered material with a pentagonal atomic arrangement, which has been very recently synthesized under high pressure (ACS Nano 15 (2021), 13,539). As a novel class of nitrogen-rich two-dimensional (2D) materials, we herein employ theoretical calculations to examine the stability of the MN2 (M = Be, Mg, Ag, Au, Fe, Ir, Rh, Ni, Cu, Co, Pd, Pt) monolayers with the pentagonal atomic arrangement. The dynamical stability and lattice thermal conductivities are examined on the basis of machine-learning interatomic potentials. The obtained results confirm the desirable stability of the NiN2, RhN2, PtN2 and PdN2 nanosheets. Analysis of electronic band structures with the HSE06 functional confirms that the NiN2, PtN2 and PdN2 monolayers are direct-gap semiconductors with band gaps of 1.10, 1.12 and 0.92 eV, respectively, whereas the RhN2 monolayer shows a metallic nature. It is predicted that the NiN2 nanosheet can exhibit a remarkably high elastic modulus, tensile strength and room temperature lattice thermal conductivity of 554 GPa, 33.1 GPa and ∼610 W/mK, respectively. The obtained first-principles results provide an extensive vision concerning the stability and outstanding physical properties of the penta-MN2 nanosheets.
•Stability, electronic, mechanical and thermal conductivity of penta-MN2 monolayers are examined.•NiN2 monolayer shows remarkably high elastic modulus, tensile strength and thermal conductivity.•NiN2, PtN2 and PdN2 monolayers are direct-gap semiconductors with band gaps of 1.10, 1.12 and 0.92 eV, respectively.