ARPES Study of the Electronic Structure of the Fe Pnictides

The iron-based layered superconductors have galvanized explosive interest in the field of high temperature superconductivity since its discovery early this year. With transition temperatures as high as 55K, this new family of compounds not only ended the monopoly of copper oxides in the high T$_{c}$ field, but also provides us a new direction to better understand the phenomenon of high temperature superconductivity. Here we present recent angle-resolved photoemission results on these iron-based layered superconductors, including direct measurements of the electronic band structures and Fermi surface topology. This new class of superconductors is different from the cuprates in that they have a high density of states near the Fermi level and have multiple bands that cross the Fermi level, which make ARPES an ideal technique to study them because of its unique capability to resolve and capture the rich information on the electronic structure in momentum space.