Iron pnictides
The discovery of superconductivity in layered iron-oxygen-arsenic compounds in early 2008 has led to tremendous experimental and theoretical efforts to understand these compounds. By now, superconductivity has been observed in many pnictides (i.e., compounds containing group-V anions) and related materials, in several cases with transition temperatures above 50 K. Like in the cuprates, it is thought that the superconductivity in doped pnictides is intimately related to the magnetic order in the undoped parent compounds. However, the electronic state is quite different from that of the cuprates. The pnictides are spin-density-wave metals, not antiferromagnetic Mott insulators.
We are interested in the spin-density-wave phase, in its interplay and coexistence with superconductivity, and in transport properties. We have also found unexpected surface states of topological origin. This work in part of our Research Training Group 1621.