Electronic band structure of GaSe(0001): Angle-resolved photoemission and ab initio theory

By performing extensive angle-resolved photoemission measurements using tunable linearly polarized synchrotron radiation with photon energies from 15 to 31 eV on high quality cleaved samples we have succeeded in experimentally mapping the occupied electronic bands of GaSe(0001) along all key symmetry directions. The experimental results are in very good agreement with state-of-the-art ab initio theoretical calculations. The data were analyzed assuming a direct transition model and final-state effects are discussed in the analysis of the normal-emission data. The off-normal emission spectra accurately reproduce the gaps in the calculated projected band structure. The azimuthal symmetry of the photocurrent revealed the polytype of the samples investigated.