A van der Waals bonded moiré bilayer formed by sequential growth of TiSe2 and TiTe2 monolayers exhibits emergent electronic structure as evidenced by angle-resolved photoemission band mapping. The two monolayers adopt the same lattice orientation but incommensurate lattice constants. Despite the lack of translational symmetry, sharp dispersive bands are observed. The dispersion relations appear distinct from those for the component monolayers alone. Theoretical calculations illustrate the formation of composite bands by coherent electronic coupling despite the weak interlayer bonding, which leads to band renormalization and energy shifts.
Keywords: emergent band structure; heterostructure; moiré bilayer; transition metal dichalcogenides; ultrathin film.