  Electronic structure of the 3x3 ordered-phase of a silicon (Si) layer on
Al(111) has been studied by angle resolved photoemission spectroscopy (ARPES)
technique using synchrotron radiation and modeled by a trial atomic model. A
closed Fermi surface originating from linearly dispersing band is identified. A
band structure calculation of a trial atomic model of the honeycomb silicene on
Al(111) implies that the metallic band originates from the Al-Si hybrid state
that has the Dirac cone-like dispersion curves. The Si layer on Al(111) can be
a model system of Xene to realize the massless electronic system through the
overlayer-substrate interaction.
