Abstracts of Bell System Technical Papers 

 Not Published in This Journal 



Deformation Potentials and Mobilities in Non-Polar Crystals * J. Bardeen^ 

 and W. Shockley.i Bibliography. Phys. Rev., v. 80, pp. 72-80, Oct. 1, 1950. 



Abstract — The method of effective mass, extended to apply to gradual 

 shifts in energy bands resulting from deformations of the crystal lattice, is 

 used to estimate the interaction between electrons of thermal energy and 

 the acoustical modes of vibration. The mobilities of electrons and holes are 

 thus related to the shifts of the conduction and valence-bond (filled) bands, 

 respectively, associated with dilations of longitudinal waves. The theory is 

 checked by comparison of the sum of the shifts of the conduction 

 and valence-bond bands, as derived from the mobilities, with the shift of 

 the energy gap with dilation. The latter is obtained independently for silicon, 

 germanium and tellurium from one or more of the following: (1) the change 

 in intrinsic conductivity with pressure, (2) the change in resistance of an 

 n-p junction with pressure, and (3) the variation of intrinsic concentration 

 with temperature and the thermal expansion coefficient. Higher mobilities 

 of electrons and holes in germanium as compared with siUcon are correlated 

 with a smaller shift of energy gap with dilation. 



Lepeth Sheath for Telephone Cables. E. J. Larsen^ and R. B. Farrell.^ 

 Elec. Engg., v. 69, pp. 1014-1017, Nov., 1950. 



Abstract — A new telephone cable sheath design has been developed by the 

 Bell Telephone Laboratories in cooperation with Western Electric engineers. 

 This sheath structure consists of a polyethylene jacket extruded on the 

 cable core, over which a relatively thin lead sheath is applied. This design 

 provides a high degree of protection against cable damage by lightning, and 

 its adoption has resulted in a reduction in costs. 



Effects of Calendar Shifts in Series of Monthly Data. C. E. Armstrong.^ 

 Am. Statistician, v. 4, pp. 20-21, Oct., 1950. 



Scattering of Electrons in Crystals in the Presence of Large Electric Fields. 

 J. BardeenI and W. Shockley.i p^^^ ^^^ ^ ^ 80, pp. 69-71, Oct. 1, 1950. 



Abstract — By the calculation of transitions between states appropriate to 

 electrons moving in a large uniform electric field superimposed on a periodic 

 crystal field, it is shown the probabilities of scattering by lattice vibrations 



*'A reprint of this'article may be obtained on request to the editor of the B. S. T. J. 

 i|B. T. L. 

 2W. E. Co. 

 3^A. T. & T. Co. 



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