Scanning Tunneling Microscopy Study ofInP(100)−(2×4): An Exception to the Dimer Model

We report the first atomic resolution scanning tunneling microscopy images of the $\mathrm{InP}\left(100\right)-(2\times 4)$ surface. High resolution images were obtained for both occupied and unoccupied states. The $\times 4$ periodicity is due to missing rows, and the $\times 2$ periodicity to the repetition of what appear to be trimer units. It is demonstrated that the images are inconsistent with dimer-based models proposed for related semiconductor surfaces such as GaAs.