ARUPS study of graphitic boron terminated WB2(0001) surface

The electronic structure of the WB2(0001) surface that is terminated with graphitic boron layer has been investigated by angle resolved ultraviolet photoelectron spectroscopy and the results were compared with predictions of the first-principles cluster and band calculations to determine its validity. 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 population analysis. It is concluded that the graphitic boron layer at the WB2(0001) surface forms π bond which is largely modified due to hybridization with the W 5d orbitals. The photoelectron spectra also show that the two types of boron layers exist in the third layer of the WB2