Outstanding thermal conductivity and mechanical properties in the direct gap semiconducting penta-NiN2 monolayer confirmed by first-principles

Abstract

Nickel diazenide NiN 2 , 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 MN 2 (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 NiN 2 , RhN 2 , PtN 2 and PdN 2 nanosheets . Analysis of electronic band structures with the HSE06 functional confirms that the NiN 2 , PtN 2 and PdN 2 monolayers are direct-gap semiconductors with band gaps of 1.10, 1.12 and 0.92 eV, respectively, whereas the RhN 2 monolayer shows a metallic nature. It is predicted that the NiN 2 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-MN 2 nanosheets. • Stability, electronic, mechanical and thermal conductivity of penta-MN 2 monolayers are examined. • NiN 2 monolayer shows remarkably high elastic modulus, tensile strength and thermal conductivity. • NiN 2 , PtN 2 and PdN 2 monolayers are direct-gap semiconductors with band gaps of 1.10, 1.12 and 0.92 eV, respectively.