Atomically Sharp\n1D Interfaces in 2D Lateral Heterostructures\nof VSe<sub>2</sub>NbSe<sub>2</sub> Monolayers

van der Waals heterostructures have emerged as an ideal\nplatform\nfor creating engineered artificial electronic states. While vertical\nheterostructures have been extensively studied, realizing high-quality\nlateral heterostructures with atomically sharp interfaces remains\na major experimental challenge. Here, we advance a one-pot two-step\nmolecular beam lateral epitaxy approach and successfully synthesize\natomically well-defined 1T-VSe<sub>2</sub>1H-NbSe<sub>2</sub> lateral heterostructures. We demonstrate the formation of defect-free\nlateral heterostructures and characterize their electronic structure\nby using scanning tunneling microscopy and spectroscopy together with\ndensity functional theory calculations. We find additional electronic\nstates at the 1D interface as well as signatures of Kondo resonances\nin a side-coupled geometry. Our experiments explored the full potential\nof lateral heterostructures for realizing exotic electronic states\nin low-dimensional systems for further studies of artificial designer\nquantum materials.