Atomic-resolution imaging of the polar (0001) surface of LiNbO_3 in aqueous solution by frequency modulation atomic force microscopy

摘要

Atomic resolution images of the polar (0001) surface of lithium niobate (LiNbO_3) are achieved by frequency modulation atomic force microscopy operated at the solid-water interface. The measured data reveal a hexagonal surface unit cell. Its lattice constant corresponds to the bulk-truncated structure, suggesting that the high-temperature annealed surface does not reconstruct. Compared to the (0001) surface, high-resolution imaging on the oppositely charged (0001) surface is considerably more difficult to achieve. This finding is rationalized by density functional calculations that indicate a higher corrugation and softer bonds on the (0001) surface compared to the (0001) surface.