Jan Korringa

Jan Korringa
Jan Korringa in 1975
Born	31 March 1915 (1915-03-31) Heemstede, Netherlands
Died	9 October 2015(2015-10-09) (aged 100) Laguna Beach, California, U.S
Occupation	Theoretical physicist
Known for	KKR method

Jan Korringa (31 March 1915 – 9 October 2015) was a Dutch American theoretical physicist, specializing in theoretical condensed matter physics. He also contributed to the KKR Method.

Korringa received his undergraduate degree from the Delft University of Technology. ^[1] In 1937, Korringa went to Leiden University, Netherlands, to pursue graduate studies. After the closure of Leiden University, Korringa returned to Delft University of Technology. In 1942, he gave a Doctor of Philosophy from Delft University of Technology and published his thesis, Onderzoekingen op het gebied algebraïsche optiek (Essays in the area of science optics).^[2] In 1946, Korringa became an associate professor at the University of Leiden. He was a protégé of Hendrik Kramers, who had been the first protégé of Niels Bohr, and who was a large influence on his interest in quantum mechanics.

In 1952, Korringa went to the United States and accepted a full professorship at Ohio State University. He was a consultant at Oak Ridge National Laboratory for many years. During the summers, he collaborated with a group at Chevron Corporation that developed nuclear magnetic resonance logging. In 1962, he was awarded a Guggenheim Foundation fellowship that he used for a sabbatical at the University of Besançon in France.^[3]

In a 1947 paper,^[4] Korringa showed how multiple scattering theory (MST) could be used to find the energy as a function of wavevector for electrons in a periodic solid. In 1954, Walter Kohn (a Nobel laureate) and Norman Rostoker (a nuclear physicist),^[5] derived the same equations using the Kohn variational method. Two of Korringa's students, Sam Faulkner^[6] and Harold Davis, started a program at the Oak Ridge National Laboratory using the Korringa-Kohn-Rostoker (KKR) band-theory equations to calculate the properties of solids.^[7]

Korringa realized that his equations could be used to calculate the electronic states of non-periodic solids for which Bloch’s theorem does not hold. In 1958 he published an approach, now called the average t-matrix approximation, for calculating the electronic states in random substitutional alloys.^[8] That work continued to evolve and was later connected to the higher-level theory called the Coherent Potential Approximation (CPA). Balázs Győrffy and Malcolm Stocks^[9] combined it with the KKR theory to obtain the KKR–CPA method, which is presently used for alloy calculations.^[10] Korringa’s MST is the basis for numerous theoretical developments, including the locally self-consistent multiple scattering theory developed by Malcolm Stocks and Yang Wang that can be used to obtain the electronic and magnetic states of any ordered or disordered solid.^[11]

In 1950, Korringa showed that the spin relaxation rate divided by the square of the magnetic resonance field shift (the Knight shift) obtained from an NMR experiment is equal to a constant, κ, times the temperature T.^[12] The magnitude of the Korringa constant κ and its possible deviation from a constant value is the signature of the effects of strong correlations in the electron gas.