Understanding porosity and temperature induced variabilities in interface, mechanical characteristics and thermal conductivity of borophene membranes

Evaluating the effect of porosity and ambient temperature on mechanical characteristics and thermal conductivity is vital for practical application and fundamental material property. Here we report that ambient temperature and porosity greatly influence fracture behavior and material properties. With the existence of the pore, the most significant stresses will be concentrated around the pore position during the uniaxial and biaxial processes, making fracture easier to occur than when tensing the perfect sheet. Ultimate strength and Young’s modulus degrade as porosity increases. The ultimate strength and Young's modulus in the zigzag direction is lower than the armchair one, proving that the borophene membrane has anisotropy characteristics. The deformation behavior of borophene sheets when stretching biaxial is more complicated and rough than that of uniaxial tension. In addition, the results show that the ultimate strength, failure strain, and Young’s modulus degrade with growing temperature. Besides the tensile test, this paper also uses the non-equilibrium molecular dynamics (NEMD) approach to investigate the effects of length size, porosity, and temperature on the thermal conductivity (κ) of borophene membranes. The result points out that κ increases as the length increases. As the ambient temperature increases, κ decreases. Interestingly, the more porosity increases, the more κ decreases. Moreover, the results also show that the borophene membrane is anisotropic in heat transfer.