خواص الکترونیکی

In this research, two new superhard metallic carbon allotropes αC28 and βC32 are predicted using density functional theory (DFT). These stable tetragonal structures belong to the P4/MMM space group. Molecular dynamics simulation performed under canonical ensemble (NVT) in order to investigate the thermal stability of new αC28 and βC32 carbon crystals at temperatures of 300 and 1000 K, confirms their thermal stability. In addition, we calculated mechanical coefficients and band gap energy of these two structures to examine their mechanical and electronic stability. These new carbon allotropes are composed of sp2 and sp3 bond hybridization, which shows excellent mechanical properties with Vickers hardness of 45.7 and 47.9 GPa. Other mechanical properties of these crystals such as bulk modulus (265.8, 284.9), shear modulus (254.7, 273.5) and Young's modulus (579.1, 621.6) also confirm the superhardness of these structures. The results related to the electronic band structures indicate that both structures have metallic properties. The width of both conduction and valance bands for both structures is about 20 eV. The results of calculations show that αC28 and βC32 can be synthesized in laboratory in the future and will have potential applications in mechanical and electronic devices.

In this paper, the optical properties of penta-boron carbide two-dimensional nanostructure (B2C) have been studied using simulations with computational codes based on density function theory based on initial calculations. The study of electronic properties shows that this two-dimensional nanostructure is an indirect semiconductor with an energy gap of 1.49 electron volts by the PBE approximation method. Study of optical properties of this nanostructure by PBE-GGA approximation method In addition to showing the agreement of optical aspects with the electronic properties of this two-dimensional monolayer, this nanostructure can in the future, as a suitable material in the design of electro-optical devices in industry Different to be used. According to the findings of this study based on the relatively high absorption rate and very low reflectivity of this nanomaterial in the visible spectrum, this nanostructure can be used for optical applications, especially in the design of solar energy devices and optical sensors with various applications in the defense industry.