Cation-rich (100) surface reconstructions of InP and GaP

The trimer reconstruction of the (100) InP surface which has been discovered experimentally is confirmed by first-principle calculations. The charge density of atomic configuration, which has the lowest surface energy is in perfect agreement with experimental scanning tunneling microscopy images. We predict the same trimer reconstruction also to be observable on GaP (100) surfaces and discuss how local stress makes this reconstruction energetically unfavorable for GaAs.