Two-dimensional Au lattices featuring unique carrier transport preference and wide forbidden gap

Large-scale 2D Au lattices with honeycomb-like structure are fabricated on Si(111)-7 × 7 surface at room temperature. The growth pattern investigated by reflection high-energy electron diffraction and in situ scanning tunneling microscopy indicates that the 2D Au lattices are composed of two interfacial distinct layers that are completely formed one after another with a close-packed structure. A unique wide forbidden gap of 4.1 eV is measured around the Fermi level of the 2D Au lattices by scanning tunneling spectroscopy. Bias-dependent STM images and theoretical simulations suggest that the in-plane quantum coupling and carrier transport behavior are responsible for the novel electronic properties. In addition to local electronic states, the electronic structures of 2D Au lattices are further modulated by the carrier transport preference that is determined by carrier energy and symmetry of 2D lattices. These findings will provide some references for the controlled fabrication and for routing the carrier transport behavior of low-dimensional metal structures.