Surface phase diagram for Cr2O3(0001):: Ab initio density functional study -: art. no. 201402

Surface phases of Cr2O3(0001) as a function of ambient oxygen pressure and temperature were computed by ab initio density-functional theory for a solid surface. The surface can be (1x1) or (root3 x root3) Cr terminated, (1x1) O terminated, and (1x1) or (root3 x root3) (O=Cr) terminated. This is the first theory of the chromyl (O=Cr) termination. The terminations critically depend on the environment, i.e., on the temperature and on the ambient oxygen partial pressure. The first-principles phase diagram is compared with a substantial number of experimental observations of surface phases.