Fig. 1. (a) Top and side views of atomic structure of monolayer BP (V_0P). The names of the zigzag-like chains and two tested atoms are marked. The upper (colored in plum) and lower (colored in light coral) chains are named nT (n is the order number of the chain) and nD, respectively. The P atoms in the upper and lower sublayers are named P_nTm (m is the order number of the atom) and P_nDm, respectively. (b) and (c) Trajectories of two tested P atoms in pristine monolayer BP under an FHEEB. (d) Top and side views of the atomic structure of a single-atom vacancy BP (V_1P) and all five tested P atoms. (e) Calculated cross-sections for the tested atoms in pristine monolayer BP (V_0P) and single-atom vacancy monolayer BP (V_1P).

Fig. 2. Atomic structures of BP with vacancies and zigzag chain vacancy. (a)–(c) Top and side views of atomic structures of BP with double-atom vacancy (V_2P), triple-atom vacancy (V_3P), and quadruple-atom vacancy (V_4P) with the tested atoms marked on them. (d) Predicted zigzag chain vacancy in monolayer BP.

Fig. 3. Electrical properties of predicted zigzag chain vacancy in monolayer BP. (a) Band structure and density of states of the chain vacancy. (b) PCD at bands MB₁ and MB₂, DCD, and atomic structure of the zigzag edge chain. (c) Band structure of double-periodic chain vacancies with and without up-and-down distortion. (c) PCD at bands MB₁ and MB₂, DCD, and atomic structure of the zigzag edge chain. (d) Top view (left) and side view (right) of the atomic structure of the chain vacancy with distortion.

Fig. 4. Five kinds of calculated edges in monolayer BP. Top views (a)–(e) and side views (f)–(j) of the atomic structures of the edges we focused on in monolayer BP. (k)–(o) Crystal directions of the corresponding edges.