Electronic structure in icosahedral AlCuLi quasicrystals and approximant crystals

The electronic structure has been calculated for large approximant crystals (up to 51752 atoms in the periodically repeated cell) to icosahedral AlCuLi quasicrystals. The results show that a deep structure-induced pseudogap at the Fermi energy is a generic property of the quasicrystal and its crystalline approximants. The physical mechanism for the formation of the gap is discussed on the basis of a quasiperiodic generalization of the nearly-free-electron model.