The bulk photovoltaic effect in the one-dimensional interface of graphene/BN superlattices

Heterointerfaces serve as critical platforms for tailoring the bulk photovoltaic effect (BPVE), especially the one-dimensional (1D) interface, which often offers high densities of states, thus resulting in superior optical responses. However, the role of the 1D interface in modulating the BPVE remains largely underexplored. Here, we investigate the BPVE in a 1D interface formed by graphene and boron nitride building blocks (graphene/BN) along the armchair direction. The system reduces to C_2v symmetry and allows for the shift current flowing along the interface of graphene/BN. The BPVE can be tailored by varying the width of the graphene/BN superlattice. Specifically, the shift current exhibits a 3-periodic enhancement with increasing width (N = 1-9). This behavior stems from Brillouin zone folding-mediated interband coupling between primary and secondary band extrema. Furthermore, the carbon stoichiometry of graphene/BN enables redshift of the shift current, effectively activating the absorption of low-energy light. Our work establishes a novel paradigm for 1D interface engineering of the BPVE.