Research trends in electron-doped cuprate superconductors

In this review, we look back on some intriguing and puzzling issues in electron-doped cuprate superconductors, such as electron- hole asymmetry, two types of carriers, quantum critical points, order-parameter symmetry, etc. The necessity of study on this family is invoked in comparison with the hole-doped counterparts from several aspects. The related progress, especially in last few years, has been outlined point to point, as well as other hot topics like the discovery of ambipolar superconductors, the applications in superconducting electronics, and the emergency of superconductivity in parent compounds. In perspective, the utilization of blooming advanced techniques, electric double layer transistor and combinatorial film deposition, will bring some new insights into the mechanism such as electron-doped cuprate superconductors.