high-temperature superconductor
/ high-TEM-per-uh-chur SOO-per-kun-DUK-ter /
For seventy years, superconductivity seemed forever chained to the deepest cold, needing liquid helium and the few-kelvin temperatures only it could reach. Then in 1986 two researchers found a brittle, layered ceramic — a material chemically more like a piece of pottery than a metal — that superconducted at a startlingly warmer temperature. Within a year, related compounds crossed the line where cheap liquid nitrogen could keep them cold, and the field was electrified.
High-temperature superconductors are mainly copper-oxide compounds, called cuprates, built from stacked planes of copper and oxygen atoms; some iron-based and hydrogen-rich materials also qualify. Their critical temperatures reach well above 90 kelvin, far higher than any ordinary metal. Crucially, their superconductivity does not seem to be glued together by lattice vibrations in the simple BCS way; the parent materials are actually insulators driven by strong electron repulsion, and superconductivity appears only when they are carefully doped.
This matters because nitrogen-temperature operation makes superconducting cables, fault limiters, and powerful magnets far more practical and affordable. The honest, humbling caveat is that after decades of intense effort, no one fully understands why the cuprates superconduct — the pairing mechanism remains unsolved. They are also ceramics: brittle, hard to form into wires, and their layered structure makes the current depend strongly on direction.
Georg Bednorz and Alex Müller discovered the first cuprate superconductor in 1986 and won the Nobel Prize the very next year — one of the fastest such recognitions in history, reflecting how shocking the result was.
The 1986 cuprate discovery earned a Nobel Prize within a year — superconductivity's biggest surprise.
Recent claims of room-temperature superconductivity in hydrogen-rich compounds rely on crushing the sample to pressures near those at Earth's centre. Even if confirmed, such materials would be of little practical use, and a room-temperature superconductor at ordinary pressure remains undiscovered.