Catalytic kinetic growth of half-metallic hexagonal boron nitride-graphene lateral heterostructure by transition metal single-atom catalyst on Rh(111)

Deciphering the precise catalytic growth mechanism of atomically thin graphene-based lateral heterostructures is of great interest in low-dimensional physics and materials. Here, based on first-principles calculations and extensive screenings, we reveal that the deposited transition metal atoms (TM=Mn, Zr, Nb, Mo, Hf, Ta, and W), particularly Mo, act as single-atom catalysts (SACs) to effectively promote C adatoms dimerization both energetically and kinetically on C-dimer-unpreferred Rh(111) substrate. Meanwhile, the TM-SAC increases the stability of boron-nitride (BN) dimer, which promotes rapid growth of hexagonal boron nitride-graphene (h-BN-G) lateral heterostructure. Specifically, taking TM=Mo as a typical example, we demonstrate that the Mo-C(BN) couplings weaken the C(BN)-substrate interactions, which sharply reduces the kinetic barriers for both C and BN nucleation and migration in the initial stage of growing h-BN-G lateral heterostructure on Rh(111). Interestingly, Mo-SAC can dynamically involve and migrate out of the h-BN-G interface during the growth processes for C₂ dimers as feeding blocks. Moreover, the presence of Mo-SAC can effectively tune the patching boundary of the 1D h-BN-G heterostructure, i.e., from C-N to C-B linking with half-metallicity. The present findings provide significantly new insights into controllable catalytic growth of two-dimensional (2D) lateral heterostructures with various important potential applications, such as transport in spintronic devices.