Atomic geometry and theoretical scanning tunneling microscopy images of K chains on InAs(110)

We have performed total-energy density-functional calculations using ab initio pseudopotentials to investigate the atomic geometry and scanning tunneling microscopy (STM) of K adsorbed on the InAs(110) surface. We have identified the most favorable adsorption geometry formed by K adatoms occupying two almost degenerate adsorption sites. Based on this structure, we have simulated the STM images showing asymmetric and zigzag chain along the ½110 direction for both negative and positive sample biases. The calculated STM images agree with the recent STM observation.