Sir Nevill Francis Mott (30 September 1905 – 8 August 1996) was a Britishtheoretical physicist who won theNobel Prize for Physics in 1977 for his work on the electronic structure of magnetic anddisordered systems, especiallyamorphous semiconductors. The Prize was shared withPhilip W. Anderson andJohn Van Vleck. The three had conducted loosely related research. Mott and Anderson clarified the reasons why magnetic or amorphous materials can sometimes be metallic and sometimes insulating.[2][3][4][5][6]
Nevill Francis Mott was born on 30 September 1905 inLeeds, England, the son ofCharles Francis Mott and Lilian Mary Reynolds, a granddaughter of SirJohn Richardson, and great granddaughter ofSir John Henry Pelly, 1st Baronet. Miss Reynolds was a Cambridge Mathematics Tripos graduate and at Cambridge was the best woman mathematician of her year. His parents met in theCavendish Laboratory, when both were engaged in physics research underJ. J. Thomson.
Nevill grew up first in the village ofGiggleswick in theWest Riding of Yorkshire, where his father was Senior Science Master atGiggleswick School. His mother also taught Maths at the School. The family moved (due to his father's jobs) first to Staffordshire, then to Chester and finally Liverpool, where his father had been appointed Director of Education. Mott was at first educated at home by his mother. At age ten, he began formal education atClifton College in Bristol,[7] followed by study atSt John's College, Cambridge—where he read theMathematics Tripos, supervised byRalph Fowler.[8]
In 1929, Mott was appointed a lecturer in theSchool of Physics at theUniversity of Manchester. He returned to Cambridge in 1930 as a Fellow of and lecturer atGonville and Caius College, Cambridge, and in 1933 moved to theUniversity of Bristol as Melville Wills Professor of Theoretical Physics. In 1948, he became Henry Overton Wills Professor of Physics and Director of the Henry Herbert Wills Physical Laboratory at Bristol. In 1954, he was appointedCavendish Professor of Physics at Cambridge, a position he held until 1971. He was instrumental in the painful cancellation of the plannedparticle accelerator because of its very high cost. He also served as Master of Gonville and Caius College, 1959–1966.[9]
His early works were on the theoretical analysis of collisions in gases, notably thecollision with spin flip of an electron against a hydrogen atom, which would stimulate subsequent works by André Blandin andJun Kondo about similar effects betweenconduction electrons, as well as magnetic properties in metals. This sort of activity led Mott to writing two books. The first one, which was edited together withIan Sneddon, gives a simple and clear description of quantum mechanics, with an emphasis on theSchrödinger equation inreal space. The second describes atomic and electronic collisions in gases, using the rotational symmetry ofelectronic states in theHartree–Fock method.
But already in the middle of the 1930s, Mott's interests had broadened to include solid states, leading to two more books that would have a great impact on the development of the field in the years prior and afterWorld War II. In 1936,Theory of the Properties of Metals and Alloys (written together with H. Jones) describes a simplified framework which led to rapid progress.[further explanation needed]
The concept ofnearly free valence electrons in metallic alloys explained the special stability of theHume-Rothery phases if theFermi sphere of thespvalence electron, treated as free, would be scattered by theBrillouin zone boundaries of the atomic structure. The description of the impurities in metals by theThomas Fermi approximation would explain why such impurities would not interact at long range. Finally the delocalisation of thevalenced electrons intransitional metals and alloys would explain the possibility for themagnetic moments of atoms to be expressed as fractions ofBohr magnetons, leading toferro orantiferromagnetic coupling at short range. This last contribution, produced at the first international conference on magnetism, held inStrasbourg in May 1939, reinforced similar points of view defended at the time in France by the future Nobel laureateLouis Néel. In 1949, Mott suggested toJacques Friedel to use the approach developed together with Marvey for a more accurate description of theelectric-field screening of the impurity in a metal, leading to the characteristic long range charge oscillations. Friedel also used the concept developed in that book of virtual bound level to describe a situation when the atomic potential considered is not quite strong enough to create a (real) bound level of symmetry e ≠ o.[further explanation needed] The consequences of these remarks on the more exact approaches of cohesion in rp as well as d metals were mostly developed by his students in Orsay.[further explanation needed]
The second book, withRonald Wilfred Gurney,On the Physical Chemistry of Solids was more wide-ranging. It treated notably of the oxidation of metals at low temperatures, where it described the growth of the oxide layer as due to the electric field developed between the metal and absorbed oxygen ions, which could force the way of metallic or oxygen ions through a disordered oxide layer. The book also analysed the photographic reactions in ionic silver compound in terms of precipitation of silver ions into metallic clusters.[citation needed]
This second field had a direct and long lasting consequence on the research activity of John (Jack) Mitchell. Mott's accomplishments include explaining theoretically the effect of light on aphotographic emulsion (seelatent image). His work on oxidation, besides fostering new research in the field (notably by J. Bénard andNicolás Cabrera), was the root of the concept of theband gap produced in semiconductors by gradients in the distribution ofdonor and acceptor impurities.[citation needed]
DuringWorld War II, Mott joined the "Army Cell" ofradar researchers. He was put in charge of getting the Army'sGL Mk. II radar working in the presence of serious calibration problems that caused the measurements to change as the antenna tracked its targets. He solved this problem by designing a large metal wire mat that was built around the radars to provide a very flat reference plane.[10]
During the war Mott worked on the role of plastic deformation in the progression of fracture cracks. When he returned to Bristol after the war, his having met and hiredCharles Frank enabled the two of them to make considerable advances in the study ofdislocations, with the help of others such asFrank Nabarro andAlan Cottrell. Bristol became an important centre of research in this topic, especially at the end of the 1940s. If Mott only produced early and somewhat minor contributions to that field, notably on alloy hardening with Nabarro and on the topology of a dislocation network lowering the apparent elastic constants of a crystal, there is no doubt that Mott's enthusiasm played its role in the three major steps forward in the field by Frank on crystal growth and plasticity and later, in Cambridge, byPeter Hirsch on thin filmelectron microscopy.[citation needed]
Mott was married to Ruth Eleanor Horder, and had two daughters, Elizabeth and Alice. Alice was an educationist who worked withClaus Moser and married the mathematician Mike Crampin, who was a professor of mathematics atThe Open University. Neville Mott retired to live near the Crampins inAspley Guise,Milton Keynes, where he died on 8 August 1996 at the age of 90. His autobiography,A Life in Science, was published in 1986 byTaylor & Francis.[11] His great grandfather was Sir John Richardson, the arctic explorer.[12]
"For his fertile application of the principles of quantum theory to many branches of physics, especially in the fields of nuclear and collision theory, in the theory of metals and in the theory of photographic emulsions."
N. F. Mott revived the oldPhilosophical Magazine and transformed it into a lively publication essentially centred on the then-new field of solid state physics, attracting writers, readers and general interest on a wide scale. After receiving a paper on point defects in crystals byFrederick Seitz that was obviously too long for the journal, Mott decided to create a new publication,Advances in Physics, for such review papers. Both publications are still active in 2017.
N. F. Mott, "The Wave Mechanics of α-Ray Tracks", Proceedings of the Royal Society (1929)A126, pp. 79–84,doi:10.1098/rspa.1929.0205. (reprinted as Sec. I-6 ofQuantum Theory and Measurement, J. A. Wheeler. and W. H. Zurek, (1983) Princeton).
