Superconductivity is a condition in which many metals, alloys, organic compounds, and ceramics conduct electricity without resistance, usually at low temperatures. Heike Kamerlingh Onnes (1853–1926), a Dutch physicist, discovered superconductivity in 1911. He was awarded the Nobel Prize in Physics in 1913 for his low-temperature studies. The modern theory regarding the phenomenon was developed by three American physicists—John Bardeen (1908–1991), Leon N. Cooper (1930–), and John Robert Schrieffer (1931–). Known as the BCS theory after the three scientists, it postulates that superconductivity occurs in certain materials because the electrons in them, rather than remaining free to collide with imperfections and scatter, form pairs that can flow easily around imperfections and do not lose their energy. Bardeen, Cooper, and Schrieffer received the Nobel Prize in Physics for their work in 1972.

A further breakthrough in superconductivity was made in 1986 by J. Georg Bednorz (1950–) and K. Alex Müller (1927–). Bednorz and Müller discovered a ceramic material consisting of lanthanum, barium, copper, and oxygen, which became superconductive at 35°K (–238°C)—much higher than any other material. Bednorz and Müller won the Nobel Prize in Physics in 1987. This was a significant accomplishment since in most situations the Nobel Prize is awarded for discoveries made as many as 20 to 40 years earlier.