Josephson effects in iron based superconductors

Just after the discovery of the iron based superconductors (iron pnictides) important differences from the conventional as well as to the high temperature superconducting cuprates were found. The complex band structure (multiple energy gaps, the unconventional symmetry of the superconducting order parameter and the unknown nature of the Cooper pair coupling mechanism) results in interesting new properties of these materials. This review summarizes the status of theoretical and experimental results on Josephson effects in the iron pnictides connected to these unusual properties. On one hand the investigation of Josephson effects can be a helpful tool to determine these properties and to test different theoretical models, but on the other hand these properties may lead to new kinds of Josephson junctions and future applications.