The interface formation between Au and cleaved (110) GaSb surfaces is investigated at low temperature (LT≪140 K) with the vibrating capacitor method. Au depositions are made in the 10-4–1 Å range. On the lightly n-type doped sample, the work function varies by around 0.74 eV in three steps, as a function of Au coverage. We suggest possible surface state distributions which can explain the experimental curves. Our analysis shows that at least three acceptor states are formed at the very beginning of Au deposition, and before reaching one monolayer. We determine the energetic position of these states, and we propose a model to explain their density evolution. © 2001 American Vacuum Society.