CO ADSORPTION ON CO(10(1)OVER-BAR-2) - A STM STUDY

Scanning tunneling microscopy (STM) studies of CO adsorption on Co(10 (1) over bar 2) at room temperature are reported. Upon adsorption of C O, added rows are found to nucleate at, and grow out from, the step ed ges of the Co(10 (1) over bar 2) surface. The added row structure exhi bits (1 x 2) periodicity in well-ordered regions. The added rows are p arallel to the [1010]-directed close-packed rows of the Co(10 (1) over bar 2) surface. Co atoms are released from the step edges to form thi s (1 x 2) structure, which never evolves to cover the whole surface. T he (3 x 1) structure, which is of the pure overlayer type, forms upon further CO dosing to coexist with the (1 x 2) structure. (C) 1998 Else vier Science B.V. All rights reserved.