Characterization of high-quality MgB2(0001) epitaxial films on Mg(0001)

High-grade MgB2(0001) films were grown on Mg(0001) by means of ultra-high-vacuum molecular beam epitaxy. Low-energy electron diffraction and x-ray diffraction data indicate that thick films are formed by epitaxially oriented grains with MgB2 bulk structure. The quality of the films allowed angle-resolved photoemission and polarization dependent x-ray absorption measurements. For the first time, we report the band mapping along the Γ-A direction and the estimation of the electron–phonon coupling constant λ = 0.55 ± 0.06 for the surface state electrons.