High-temperature superconductor

High-temperature superconductors shattered the conventional wisdom that superconductivity required temperatures near absolute zero. When Georg Bednorz and K. Alex Müller discovered superconductivity in ceramic oxides at IBM Zürich in 1986, they triggered a scientific revolution that culminated in the 'Woodstock of Physics' and the fastest Nobel Prize ever awarded.

The adjacent possible emerged from an unconventional approach. For decades, superconductivity research focused on metal alloys, pushing critical temperatures (Tc) incrementally upward but never above 23K. Bednorz and Müller took a different path: in 1983, they began systematically studying ceramic transition metal oxides. In February 1986, they observed superconductivity at 35K in lanthanum barium copper oxide (LBCO)—not just a temperature record, but a paradigm shift. Ceramics weren't supposed to superconduct at all.

The paper 'Possible high-Tc superconductivity in the Ba−La−Cu−O system' appeared in Zeitschrift für Physik B. Initially, the physics community was skeptical. But when Paul Chu at the University of Houston confirmed LBCO superconducting at 40K in December 1986—and observed fluctuations suggesting higher temperatures were possible—the race was on.

On January 29, 1987, Chu's colleagues at the University of Alabama in Huntsville synthesized yttrium barium copper oxide (YBCO). It superconducted at 92K—above the 77K boiling point of liquid nitrogen. This was the breakthrough that mattered for applications: liquid nitrogen costs about the same as milk, while liquid helium (required for conventional superconductors) costs as much as fine whiskey.

The cascade was unprecedented. When Chu's paper was initially rejected for length, Neil Ashcroft organized an emergency session at the March 1987 American Physical Society meeting. The 'Woodstock of Physics' drew overflow crowds; bars near the New York Hilton opened to accommodate physicists discussing superconductivity. Camera flashes lit presenters' faces as Müller, Chu, and Japanese physicist Shoji Tanaka announced their results.

Nineteen months after submitting their paper, Bednorz and Müller received the call from Stockholm—the shortest gap between discovery and Nobel Prize in physics history. The 1987 Nobel recognized them 'for their important break-through in the discovery of superconductivity in ceramic materials.'

Path dependence shaped subsequent development. YBCO became the standard high-Tc material, though it proved difficult to manufacture into practical wires and devices. By 2026, high-temperature superconductors power MRI machines, particle accelerator magnets, and experimental power transmission lines—a testament to Bednorz and Müller's willingness to look where conventional wisdom said not to.