High Temperature Superconductivity

Abstract

The discovery of superconductivity at 93 °K in early 1987 represents one of the most exciting developments in modern physics. I shall first describe some events in the long search for superconductors with a high transition temperature (Tc) before 1986 that are important to later progress in high temperature superconductivity (HTS). I recall crucial steps taken surrounding 1986 — the critical year of HTS when George Bednorz and Alex Muller made their seminal observation of superconductivity at 35 °K in a nonconventional oxide, that preceded the exciting discovery in 1987. I also recount some episodes from 1987 — the exciting year of HTS when the 93 °K superconductors were discovered and studied. Finally, several major compound systems that were responsible for the solid advancement of Tc and better understanding of HTS in the period of 1988–1994 are summarized. At present, I know of neither experimental nor theoretical reasons for not being able to achieve superconductivity at temperature higher than the present record of 134 °K and 164 °K at ambient and high pressures, respectively.