First-principles calculation study on the stabilities of the (100) and (111) surfaces of boron-doped diamond

Boron-doped diamond (BDD) has attracted much attentions in semi-/super-conductor physics and electrochemistry, where the surface structures play crucial roles. Herein, we systematically re-examined the probable surface reconstructions of the bare and H-terminated BDD(100) and (111) surfaces by using density functional theory (DFT). For the optimized structures, we performed STM image simulations based on Tersoff-Hamman scheme and calculations of the projected density of states. We found that: on the BDD(100), the p(2x1) reconstruction has lowest energy and the c(2x2) reconstruction has 0.1673 eV/surface-atom energy higher; On the BDD(111), the ideal (1x1) has lowest energy, the single chain SC-(2x1) and Pandey chain PC-(2x1) have 0.3415 eV/surface-atom and 0.6576 eV/surface-atom higher energy, respectively. The BDD(111) appears to have more reconstructions than the BDD(100) which supports to the idea that the BDD(111) is more electrochemically reactive than the BDD(100). In addition, we study the impact of the Boron dopant on the surface states of the BDD(111) and suggest the Boron-enhanced graphitization on the BDD(111). The results give an insight into the surface stability of the BDD.