Tuning Band Gap and Work Function Modulations in Monolayer hBN/Cu(111) Heterostructures with Moire Patterns

The moire pattern formed between a two-dimen-sional (2D) material and the substrate has played a crucial role in tuning the electronic structure of the 2D material. Here, by using scanning tunneling microscopy and spectroscopy, we found a moire-pattern-dependent band gap and work function modulation in hexagonal boron nitride (hBN)/Cu(111) heterostructures, whose amplitudes increase with the moire pattern wavelength. Moreover, the work function modulation shifts agree well with the conduction band edge shifts, indicating a spatially constant electron affinity for the hBN layer. Density functional theory calculations showed that these observations in hBN/Cu(111) heterostructures mainly originated from the hybridization of the N 3p(z) orbital and Cu 4s orbital in different atomic configurations. Our results show that the twist-angle dependence of moire patterns in hBN/Cu(111) heterostructures can be used to tailor the electronic properties including band gap and work function.