Si(100)-2 x 1-H dimer rows contrast inversion in low-temperature scanning tunneling microscope images

Detailed low temperature scanning tunneling microscope images of the Si(100)-2 x 1-H surface show a remarkable contrast inversion between filled- and empty-state images where the hydrogen dimer rows appear bright for filled-state images and dark for empty-state images. This contrast inversion originates from the change in the dominant surface states and their coupling to the tip apex and the bulk silicon channels as a function of the bias voltage: dimer Si-Si bonding states dominate the filled-state images and valley states associated with Si-Si anti-bonding states dominate the empty-state images. Care is required when constructing and interpreting the atomic structure of dangling-bond structures on the Si(100)-2 x 1-H surface.