Surface structure and composition of the missing-row reconstruction of VC0.8(1 1 0) : A LEED, GIXRD and photoemission study

• Low energy electron diffraction, grazing incidence X-ray diffraction and photoemission were used to decipher the detailed structural arrangement and chemical composition of the surface region of a transition metal carbide, VC0.8(1 1 0). In agreement with previous scanning tunneling microscopy (STM) studies, we find that the surface reconstructs with a ridge-and-valley grating structure along the [1 over(1, ¯) 0] direction resulting from {0 0 1} faceting for the (3 × 1) and the (4 × 1) phases. Both superstructures terminate on the vacuum side with a nearly stoïchiometric VC region due to C segregation, in contrast with the conclusions drawn from this previous STM study. However, the present experiments clearly show that these phases are metastable, and slow cooling results in a (1 × 1) surface, which is highly C depleted, similarly to the (1 0 0) face. © 2007 Elsevier B.V. All rights reserved.

Nyckelord

Carbide

Low energy electron diffraction

Photoemission

Surface relaxation and reconstruction

Surface segregation

Surface X-ray diffraction

Vacancy

Vanadium

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