High-temperature superconductors: from “copper age” to “iron age”

Superconductivity was discovered in 1911 by H. Kamerlingh Onnes in Leiden, which aroused extensive interests in the field of condensed matter physics and boosted the development of modern sciences and technologies. Almost half century after this great discovery, a complete and satisfactory theoretical picture of the classic superconductors were established. The second round of boom emerged in 1986 when high-temperature superconductivity was discovered in copper oxides by Bednorz and Müller (“copper age”). These new superconductors have superconducting transition temperatures (Tc) much higher than the prediction for the classic or conventional superconductors, and behave strangely in many aspects. Up to now, the high-Tc mechanism in copper oxides is still in controversial. Recently, iron-based high-temperature superconductors were discovered providing a new platform to understand high-Tc mechanism. In this talk, I will give brief introduction to the fascinating field of superconductivity and current status, following by our own work of using scanning tunneling microscopy / spectroscopy to verify the mechanism of high-temperature superconductors.