Colloquia

Recent discovery of iron-based high temperature superconductors hints at a new pathway to the room temperature superconductivity. The new materials feature FeAs layers instead of the signature CuO2 planes of much-studied cuprate superconductors. The antiferromagnetism also appears to be involved, although the d-electrons in FeAs seem considerably more mobile than their cuprate cousins. This high mobility, facilitated by a large overlap between atomic orbitals of Fe and As, plays a crucial role in warding off Hund's rule and the large local moment magnetism of Fe ions, the archrival of superconductivity. I will present a pedagogical review of the current status of the field, highlighting similarities and differences between iron pnictides and cuprates, and emphasizing the importance of the multiband nature of magnetism and superconductivity in these new materials.