(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).