Progress and perspectives on electron-doped cuprates

Although the vast majority of high-${T}_{c}$ cuprate superconductors are hole-doped, a small family of electron-doped compounds exists. Underinvestigated until recently, there has been tremendous recent progress in their characterization. A consistent view is being reached on a number of formerly contentious issues, such as their order-parameter symmetry, phase diagram, and normal-state electronic structure. Many other aspects have been revealed exhibiting both their similarities and differences with the hole-doped compounds. This review summarizes the current experimental status of these materials. This information is synthesized into a consistent view on a number of topics important to both this material class and the overall cuprate phenomenology including the phase diagram, the superconducting order-parameter symmetry, electron-phonon coupling, phase separation, the nature of the normal state, the role of competing orders, the spin-density wave mean-field description of the normal state, and pseudogap effects.