Univ Sci & Technol China, Struct Res Lab, Hefei 230026, Peoples R China
; Univ Sci & Technol China, Natl Synchrotron Radiat Lab, Hefei 230029, Peoples R China
; Acad Sinica, Inst High Energy Phys, Beijing 100039, Peoples R China
An electronic structure investigation on GaN(0001) is reported: We employ a full-potential linearized augmented plane-wave(FPLAPW) approach to calculate the partial density of states, which is in agreement with previous experimental results. The effects of the Ga3d semicore levels on the electronic structure of GaN are discussed. The valence-electronic structure of the wurtzite GaN(0001) surface is investigated using synchrotron radiation excited angle-resolved photoemission spectroscopy. The bulk bands dispersion along FA direction in the Brillouin zones is measured using normal-emission spectra by changing photon-energy. The band structure derived from our experimental data is compared well with the results of our FPLAPW calculation. Furthermore, off-normal emission spectra are also measured along the GammaX and GammaM directions. Two surface states are identified, and their dispersions are characterized.