ARUPS study of graphitic boron terminated WB2(0001) surface

The electronic structure of the WB2(0001) surface that is terminated with g raphitic boron layer has been investigated by angle resolved ultraviolet ph otoelectron spectroscopy and the results were compared with predictions of the first-principles cluster and band calculations to determine its validit y. The occurrence of the charge transfer from W to B, leading to large work function (6.1 eV) of the WB2(0001) surface, is confirmed from Mulliken pop ulation analysis. It is concluded that the graphitic boron layer at the WB2 (0001) surface forms pi bond which is largely modified due to hybridization with the W 5d orbitals. The photoelectron spectra also show that the two t ypes of boron layers exist in the third layer of the WB2. (C) 2000 Elsevier Science B.V. All rights reserved.