Esaki, Leo, 1925–, Japanese physicist, Ph.D. Univ. of Tokyo, 1959. Esaki was a researcher with IBM from 1960 until his retirement in 1992. He then served (1992–98) as president of the Univ. of Tsukuba in Japan, and in 2000 accepted a five-year appointment as president of the Shibaura Institute of Technology. Esaki received the 1973 Nobel Prize in Physics, along with Ivar Giaever and Brian Josephson, for his discovery in 1958 of the phenomenon of electron tunneling—in which an electron passes through a narrow region of a solid, where classical theory predicts it could not pass—in semiconductors. He exploited this effect to create the tunnel, or Esaki, diode, which has been used in a number of electronics applications, including microwave devices and computers.