Electronic structure and optical properties of Al are reexplored by using the highly precise first-principles band method. The spin-orbit interaction, albeit small, plays a critical role in determining the topology of the Fermi surface and yields finite gap for interband transitions. The characteristic optical peaks in Al are shown to arise from the massive interband transitions between two parallel bands over the nested area of two Fermi surfaces. The laser-induced structural transition originates from this massive interband transition which causes the lattice softening via the excitation-driven charge transfer from the tetrahedral bonding to the octahedral antibonding sites.

• Received 22 September 2003

DOI:https://doi.org/10.1103/PhysRevB.69.033101