Contains reports on two research projects

Gyorgy, E. M.

Harvey, George G.

Kingston, R. H.

Meckler, A.

Piore, E. R.

Tisza, Laszlo

DSpace@MIT

III. SOLID STATE PHYSICSProf. G. G. Harvey E. M. GyorgyProf. L. Tisza R. J. HarrisonDr. E. R. Piore R. H. KingstonA. MecklerA. THE THEORY OF SUPERCONDUCTIVITYThe well known phenomenological theory of F. and H. London leads torather severe restrictions for the electronic wave functions which mightpossibly account for the phenomenon of superconductivity. Yet all attemptsto construct such wave functions according to the principle of quantummechanics have been so far unsuccessful. This failure seems to stem fromthe use of one-electron functions for a problem for which the electronicinteraction is of great importance. It was generally assumed that the manyelectron wave functions are too difficult to handle.Actually, the Bloch-Slater theory of ferromagnetism required the useof many electron functions, but these were not associated with any currentand thus were not appropriate for a theory of either normal- or super-con-ductivity.We have introduced a new type of many-electron function which containsthe previously used wave functions as special cases but includes situationswhich eluded the earlier theories. The general nature of these wave func-tions precludes a too specific calculation. The discussion has been con-fined rather to an investigation of the properties of the functions withrespect to the group of crystal translations. The current-carrying proper-ties of the corresponding electronic states essentially follow from thesetranslational symmetry properties.The formalism provides the possibility of states which, according topreliminary investigations, appear to have the electric, magnetic andthermal properties of superconductors. The work is being continued.L. TiszaB. SOFT X-RAY VACUUM SPECTROGRAPHThe pumping systems for the vacuum spectrograph and x-ray enclosuresare under test. The spectrograph chamber is fitted with a six-inch-diame-ter metal, oil diffusion pump, and the x-ray tube with a similar three-inch pump. Both diffusion pumps are backed by glass single-stage oilbooster pumps.The slit system, the diffraction grating holder, and other mechanicalparts of the optical system have been fabricated and are in the process ofassembly. The grating has a two-meter radius and is ruled on glass with-17-(III. SOLID STATE PHYSICS)30,000 lines per inch. It was ruled by R. W. Wood and is the same one usedby O'Bryan and Skinner in their soft x-ray work at M.I.T. some years ago.It is planned to use as the detecting element a beryllium-coppereleven-stage electron multiplier that will travel along the Rowland circle,preserving its orientation with respect to the tangent. The driving mech-anism for this motion has been completed, but has not yet been tested forreproducibility of setting. Other components, such as amplifiers and powersupplies, have been constructed. Provision has also been made for photo-graphic recording.An electron gun with the desired spot size, and current and voltagecharacteristics, is still in the experimental stage.G. G. Harvey, E. R. Piore, E. M. Gyorgy, R. H. Kingston, A. Meckler-18-

Solid State Physics

http://dspace.mit.edu/bitstream/1721.1/50827/1/RLE_QPR_015_III.pdf

Solid State Physics

Abstract

Similar works

Full text

Available Versions

DSpace@MIT