c ABSTRACTS OF PAPERSTO APPEAR fl~J. PHYS. CHEM. SOLIDS Vol. 3, N~

a! Fe~ions at tetrahedralsites. which adeterminationolthe sp~-orbitsplitcouldbe made. From theboron-dopedsami

(Received9 July 1965) the value0 037 eV wasobtainedfor the spinorbit-splittingat 88?K. Thevalue0.0383e’wasobtainedfor the spin-orbitsplitting at 3

12. Dfl’ERBAND FARADAY ROTATION OF and88°Kfrom the absorptionbind dueto tifl-VI COMPOUNDS. sitionsfrom the v1 - to the v3 -band, when thM. Be1b~n~, E. AmzallagandD. Langer, InterbandabsorptionIn anintrinsic sample(Laboratoirede Physique,EcoleNorinale recorded From this band a determinationSup~rieure,Paris Ve). the effectivehole massIn the split-off band

could be made, andat88°K the value 0.42i•Interband magnetic rotatory polarization wasobtained.

is measuredin ZnS, ZuSe, CdSand ZnTe at90°Kand 290°K. In eachof thesematerials, (Received12 July 1965)the specificrotation Is found to be positive andto Increasemonotonically where scanningfrom0.5 eV toward higher energy,upto thefunda- 14. ULTRASONIC ATTENUATION IN SODImental absorptionedge. The experimental AT LOW TEMPERATURES.results arecompared with the rotation deduced RichardStern,GiovanG. Natale, andfrom theoretical considerations,t~irhtg into IsadoreRudnick (PhysicsDepartment,accountthe band structure The anslysisshows University of California, LosAngeles,that 511valencebanda contributeto the rotation. Calif rnla).

The magnitudeof the Verdet coefficient The ultrasonicattenuation In a wire &leadsto thederivation of an effective g-valuefor pie of sodiumwasmeasuredby pulse-echo~eachband, and an effective energygapfor each resonanttechniquesover a temperature ranimaterial, of 2°- 77°Katfrequenciesof 150-300kc in

order to Investigatetheeffectsof the marte(Received8 April 1965) attic transformationandthe electron-lattice(RevIsed12 July 1965) Interaction. The onsetof the transformatio

into the low temperatureh. c. p. structurewindicated by an Increase In the attenuation w

13. DETERMINATION OF TEE SPIN-ORBIT then decreasedasabsolute zero wasapproaSPLiTTING IN THE VALENCE BAND OF The attenuationdisplayeda pronouncedhystiSILiCON BY MEANS OF INFRA-RED esiswith thermal cycling, reverting lrrevezABSORPTION. into the high temperature phase,b. c. c., atTorsten Staflln (PhysicsDepartment and about 52°K. Qualitative agreementwith theiInstituteof Optical Research, Royal was found for the electron-lattice interactioiInstituteof Technology, Stockholm 70, A metastablestateof sodium was formed duSweden). extrusion of the sodiumwire at liquid nitrog

tem’peratures; it consistedof body-centerecThe absorption measurementsweremade cubic andhexagonalclose-packedstructure~

on intrinsic asweUas on boron- and indium- evidencedby ultrasonic velocity, specifich~doped silicon in the wavelengthinterval 1 - 35~.im andx-ray diffraction experiments. At aboulandwith temperatures between30°Kand 330°K. 116°K, the metastablestatebeganto revertThe measurementswere performedwith a into the b. c. c. structure, the usual state ofmethod, where free carriers were excitedby sodium at thesetemperatures.light with photon-energy greater thanthefunda-mental band gap, and the resultingabsorption (Received13 April 1965)changewas recorded[s,io] . Threeindepend- (Revised28 July 1965)ent determinationsof the spin-orbit splitting inthevalenceband weremade. The methodmadeit possibleto eliminate the titer- and infra-band 15. ELECTRON SPIN RESONANCE IN Aabsorptionandrecordthe absorption due to METAL AS MODIFIED IN THE NEARtransitionsfrom impurity levelsto the valence ANOMALOUS SKIN DEPTH REGION.band. In boron- andIndium-dopedcrystalsan Jerome L Kaplan(Department of Physiabsorptionbanddue to transitionsfrom the tin- BrownUniversity, Providence,Rhodepurity levelsto thev3-bandwasdetectedfrom Island).