Structure and local-equilibrium thermodynamics of the c(2x2) reconstruction of rutile TiO2 (100)

We resolve the structure of a c(2 x 2) reconstruction of the rutile TiO(2) (100) surface using a combination of transmission electron diffraction, direct methods analysis, and density functional theory. The surface structure contains an ordered array of subsurface oxygen vacancies and is in local thermodynamic equilibrium with bulk TiO(2), but not the with oxygen gas-phase environment. The transition into a bulklike (1 x 1) reconstruction offers insights into the time-dependent local thermodynamics of TiO(2) surface reconstruction under global nonequilibrium conditions.