K. Alex Müller
Nobel Prize in Physics 1987

New Direction in Sicily

A flash of inspiration while in Sicily put K. Alex Müller on the right track: Soon afterwards, he and J. Georg Bednorz discovered the first high-temperature superconductor.

In 1986 K. Alex Müller and J. Georg Bednorz revolutionized solid-state physics with the discovery of the first high-temperature superconductor. Their breakthrough came after three years of hard work at the IBM research laboratory in Rüschlikon, 80 synthesized compounds, and multiple set-backs. Lanthanum-barium-copper oxide was the compound that took superconductor research in entirely new directions. The two researchers discovered that the critical temperature at which this copper oxide becomes superconductive is an astonishingly high minus 238 degrees – nothing short of sensational. The publication of their research unleashed a wave of enthusiasm, and laboratories around the world began to work with the findings. Soon, copper oxides with even higher critical temperatures were found.

The highest critical temperature discovered for copper oxides is now minus 110 degrees Celsius. A high critical temperature has the advantage of enabling superconductivity through cooling with liquid nitrogen, making technical applications much simpler and cheaper. It is used today in power stations, transformers, medical technology, power transmission and microelectronics.

K. Alex Müller became interested in superconductor research relatively late in life, when he was 56. He was then already a recognized figure in solid-state physics, an IBM Fellow, and adjunct professor at the University of Zurich.

The idea of looking for superconductivity in copper oxides came to him at a conference in Erice, in Sicily. It seemed far-fetched, as oxides are ceramic substances with only very poor conductivity at normal temperatures. After his return from Sicily, however, Müller took Bednorz into his confidence. Then 33, Bednorz, Müller’s former doctoral student, was also working at the IBM laboratory in Rüschlikon. The two researchers initiated the superconductor project confidentially, as a so-called “submarine project.” Three years later, they achieved their objective. In the following year, 1987, they were jointly awarded the Nobel Prize in Physics, just months after Müller had been appointed full professor at the University of Zurich.