Two predicted two-dimensional BCN structures: A first-principles study

Abstract

Two predicted two-dimensional (2D) BCN structures are theoretically investigated, denoted as B 6 C 6 N 6 -1 and B 6 C 6 N 6 -2. The former and the later belong to space groups P 6 ‾ 2 m and P 3 ‾ 1 m , respectively. Both phonon dispersion plots have no imaginary frequencies, revealing that they are dynamically stable. The elastic constants indicate that both BCN structures are also mechanically stable. The ab initio molecular dynamics simulations indicate that two BCN systems not only have good thermal stability at room temperature but also at a relatively high temperature (1000 K). The values of in-plane stiffness for B 6 C 6 N 6 -1 and B 6 C 6 N 6 -2 are 290 and 286 N/m, respectively. Both B 6 C 6 N 6 -1 and B 6 C 6 N 6 -2 are indirect semiconductors, possessing their indirect band gaps of 3.54 eV and 3.71 eV (HSE06), respectively. Therefore, due to their electronic properties, large in-plane stiffness and thermal stability at 1000 K, both 2D BCN systems may provide semiconducting and mechanical applications, and the usage at high temperature as well. •Two 2D BCN structures are predicted to be stable. •They are indirect semiconductors with band gaps of 3.54 eV and 3.71 eV. •They have large in-plane stiffness (290 and 286 N/m). •They have good thermal stability not only at 300 K but also at 1000 K. • They may have potential semiconducting and mechanical applications, and the usage at high temperature.