John Bardeen

Bardeen was the theorist of the pair that built the point-contact transistor in 1947; it was his grasp of surface states in semiconductors that told Brattain where the contacts should go. For that he shared the 1956 physics prize with Brattain and Shockley. The partnership with Shockley soured, and in 1951 Bardeen left Bell Labs for the University of Illinois, worn down by his manager's need for control.

There he took on a problem that had resisted attack for forty years: superconductivity. With Leon Cooper and Robert Schrieffer he formulated BCS theory in 1957, explaining how electrons pair up and flow without resistance. It won him a second physics prize in 1972 — still the only two in the same field. For all that, Bardeen was so self-effacing that his neighbours barely knew what he did for a living.