A novel two-dimensional C36 fullerene network; an isotropic, auxetic semiconductor with low thermal conductivity and remarkable stiffness

The synthesis of two-dimensional (2D) C60 fullerene network (Nature (2022), 606, 507) with an anisotropic lattice is among the most exciting advances in the field of carbon-based materials, which has the potential to expand and establish a new class of 2D materials. In this work, a novel C36 fullerene 2D network with an isotropic structure is designed by screening of extensive and diverse fullerene lattices. Density functional theory calculations confirm that the herein predicted C36 fullerene network can exhibit an outstanding thermal stability up to 1500 K, an elastic modulus of 266 GPa, a negative Poisson's ratio of −0.05, and an indirect semiconducting electronic nature, with a HSE06(PBE) bad gap of 1.63 (0.97) eV. The phonon dispersion relation, mechanical and failure responses, and lattice thermal conductivity are explored with the aid of machine learning interatomic potentials (MLIPs). MLIP-based calculations close to the ground state confirm the dynamical stability, a negative Poisson's ratio of −0.06, an elastic modulus of 269 GPa, and a high tensile strength of around 26.8 GPa for the predicted 2D network. Room temperature phononic thermal conductivity and tensile strength are also predicted to be 9.8 ± 1 W/m.K and 15.9 GPa, respectively. This study introduces a novel isotropic and auxetic semiconducting full-carbon nanoporous nanosheet, with low thermal conductivity and appealing electronic, optical, and mechanical features, highlighting a bright prospect for the design and synthesis of novel fullerene-based 2D networks.