Table of contents

20 November 1995, Volume 4 Issue 11 Previous issue    Next issue

GENERAL

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REALIZATION OF THE WAVE-PACKET-COLLAPSE —A VIEWPOINT TO THE QUANTUM MEASUREMENT THEORY DUAN LU-MING (段路明), GUO GUANG-CAN (郭光灿) Acta Physica Sinica (Overseas Edition), 1995, 4 (11):  801-805.  DOI: 10.1088/1004-423X/4/11/001 Abstract ( 1261 )   PDF (122KB) ( 386 )   An interpretion of the wave-packet-collapse (WPC) in the system of quantum mechanics is given. We find a connection between the WPC and the limitation to the measurement precision determined by the quantum fluctuation. A simple and explicit relation about them is obtained.

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NORMAL-INCIDENCE QUANTUM WELL INFRARED PHOTODETECTOR WITHOUT GRATING COUPLER WANG WEN-XIN (王文新), HU QIANG (胡强), HUANG QI (黄绮), ZHOU JUN-MING (周均铭), CUI DA-FU (崔大复), CHEN ZHENG-HAO (陈正豪) Acta Physica Sinica (Overseas Edition), 1995, 4 (11):  806-809.  DOI: 10.1088/1004-423X/4/11/002 Abstract ( 1215 )   PDF (106KB) ( 428 )   The n-type GaAs/AlxGa1-xAs multiple quantum well infrared photodetectors have been demonstrated without any grating couplers. We have achieved a responsivity Rv of 1.7×105V/W and a detectivity D$\lambda$* of 4.0×1010 cm (Hz)1/2/W for a wavelength of 8.4 μm at a temperature T = 77 K in normal incidence.

CLASSICAL AREAS OF PHENOMENOLOGY

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EFFECTIVE CAVITY LENGTH IN VERTICAL CAVITY SURFACE EMITTING LASER PAN ZHONG (潘钟), WU RONG-HAN (吴荣汉), WANG QI-MING (王启明) Acta Physica Sinica (Overseas Edition), 1995, 4 (11):  810-815.  DOI: 10.1088/1004-423X/4/11/003 Abstract ( 1221 )   PDF (148KB) ( 365 )   Effective cavity length method is introduced to vertical cavity surface emitting laser for characterizing some properties, including reflectivity, FWHM, mode wavelength and thresh-old gain. Some experiment results are demonstrated, showing the agreement of theoretical analysis with experiment.

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

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GENERALIZATION OF ESHELBY'S METHOD TO THE ANISOTROPIC ELASTICITY THEORY OF DISLOCATIONS IN QUASICRYSTALS DING DI-HUA (丁棣华), QIN YUE-LING (秦越岭), WANG REN-HUI (王仁卉), HU CHENG-ZHENG (胡承正), YANG WEN-GE (杨文革) Acta Physica Sinica (Overseas Edition), 1995, 4 (11):  816-824.  DOI: 10.1088/1004-423X/4/11/004 Abstract ( 1098 )   PDF (217KB) ( 426 )   The general expressions of the elastic fields induced by straight dislocations in quasicrystals have been given according to Eshelby's method which was used to treat the anisotropic elasticity of dislocations in crystals. As an example, the elastic displacement vector, the stress tensor and the elastic energy density of a screw dislocation line lying on the quasiperiodic plane of decagonal quasicrystals are calculated.

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GAS DYNAMIC PROBLEMS CAUSED BY THE GENERATION OF THE RADICALS IN A SUPERSONIC JET LIU SHI-LIN (刘世林), ZHANG LI-MIN (张立敏), CHEN CONG-XIANG (陈从香), MA XING-XIAO (马兴孝), ZHU NIAN-LIN (朱念麟) Acta Physica Sinica (Overseas Edition), 1995, 4 (11):  825-833.  DOI: 10.1088/1004-423X/4/11/005 Abstract ( 1103 )   PDF (223KB) ( 390 )   A simplified one-dimensional model was proposed to treat the gas dynamic problems in a supersonic jet, which was used to produce radicals cooled by supersonic expansion, Based on this model, the gas dynamic equations can be integrated directly to obtain the evolution or the translational temperature and the rotational temperature of free radicals as well as the molecule density. The results show that the heating position where the radicals are generated and the initial rotational temperature of radicals have little effect on the rotational temperature at the down stream detection point, if the heating position is close to the nozzle orifice.

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

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BAND STRUCTURES OF Si-C AND Si-C-Ge ALLOYS XIE JIAN-JUN (谢建军), ZHANG KAI-MING (张开明) Acta Physica Sinica (Overseas Edition), 1995, 4 (11):  834-841.  DOI: 10.1088/1004-423X/4/11/006 Abstract ( 1217 )   PDF (251KB) ( 332 )   Band structures of Si-C and Si-C-Ge alloys are calculated by using the ab initio LMTO (linear muffin-tin orbital) method within the framework of atomic-sphere approximation. The effects of different atomic configuration and lattice relaxation on the band structure of alloys are taken into account. The results show that for large concentrations of C in Si and Si-Ge, the band gap increases monotonically, while for small concentrations of C in Si and Si-Ge, the band gap shrinks. The lattice relaxation further reduces the band gap. The possible explanations for the reduction of band gap of Si-C and Si-C-Ge alloya are presented.

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CRITICAL EXPONENTS OF THE ONE-DIMENSIONAL CONTINUUM HEISENBERG-ISING MODEL ZHANG YU-MEI (章豫梅), XU BO-WEI (许伯威) Acta Physica Sinica (Overseas Edition), 1995, 4 (11):  842-846.  DOI: 10.1088/1004-423X/4/11/007 Abstract ( 1178 )   PDF (122KB) ( 363 )   The continuum generalization of the one-dimensional Heisenberg-Ising model is studied by the bosonization method. With reference to the results of the renormalization group theory, we are able to obtain the critical exponents by considering the influence of the large momentum transfer and improve Luther and Peschel's results to the next order. A comparison of the exact result of the lattice model with that of the continuum model by various treatments are also given.

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MULTI-ACTIVATION ENERGY DENSITY DISTRIBUTION AND THERMALLY STIMULATED CURRENT OF ELECTRIC DIPOLES IN CONDENSED MATTER LIU FU-DE (刘付德), LING ZHI-YUAN (凌志远), XIONG MAO-REN (熊茂仁) Acta Physica Sinica (Overseas Edition), 1995, 4 (11):  847-855.  DOI: 10.1088/1004-423X/4/11/008 Abstract ( 1162 )   PDF (215KB) ( 340 )   The physical meaning of the transcendental function in traditional thermally stimulated current (TSC) equation of electric dipoles with a single activation energy was first analyzed. Then a simple formula obtained directly from the tested TSC for calculating activation energy parameter, etc., was deduced. Numerical calculation showed that the exact TSC agrees with the approximated one very well. Further analysis found a limiting condition for the discrete to continuous activation energy density distribution and a criterion for discriminating the contributions to TSC by depolarization of the dipoles with multi-activation energy from those with a single one.

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ELECTROLUMINESCENCE SPECTRA OF GexSi1-x/Si SINGLE QUANTUM WELL CHENG WEN-QIN (程文芹), CUI QIAN (崔堑), CAI LI-HONG (蔡丽红), HU QIANG (胡强), ZHOU JUN-MING (周均铭) Acta Physica Sinica (Overseas Edition), 1995, 4 (11):  856-858.  DOI: 10.1088/1004-423X/4/11/009 Abstract ( 1244 )   PDF (74KB) ( 368 )   The electroluminescence of GexSi1-x/Si single quantum well was measured at temper-atures above room temperature along the growth direction and the direction normal to it. TO and NP peaks were resolved.

CROSS DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY

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PASSIVATION OF THE InP(100) SURFACE USING (NH4)2Sx CHEN WEI-DE (陈维德), XIE KAN (谢侃), DUAN LI-HONG (段俐宏), XIE XIAO-LONG (谢小龙), CUI YU-DE (崔玉德) Acta Physica Sinica (Overseas Edition), 1995, 4 (11):  859-863.  DOI: 10.1088/1004-423X/4/11/010 Abstract ( 1256 )   PDF (127KB) ( 371 )   InP(100) surface treated with (NH4)2Sx has been investigated by using photolumines-cence(PL), Auger electron spectroscopy and X-ray photoelectron spectroscopy, It is found that PL intensity increased by a factor of 3.3 after (NH4)2Sx passivation and the sulfur remained on the surface only bonded to indium, not to phosphorus. This suggests that the sulfur atoms replace the phosphorus atoms on the surface and occupy the phosphorus vacancies.

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

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RAMAN SCATTERING OF ORGANIC CHARGE-TRANSFER SALTS CONTAINING BEDT-TTF CATION LIU DAO-ZHI (刘道志), W. HAYES Acta Physica Sinica (Overseas Edition), 1995, 4 (11):  864-869.  DOI: 10.1088/1004-423X/4/11/011 Abstract ( 1388 )   PDF (176KB) ( 370 )   Raman scattering of several organic charge-transfer salts containing BEDT-TTF of ET cation such as $\kappa$-ET2Cu(NCS)2, $\beta$L-ET2I3, $\alpha$-ET3Cl2. 2H2O, $\alpha$-ET3 (ReO4)2 and ETFeBr4 were measured and the variations of the frequencies of C=C bonds of ET molecules on charge transfer were observed. It is found that the energy of C=C stretch modes shows a general downward shift upon ionisation of ET molecule. In addition, we have observed the Raman spectra of C=C stretch vibratinns in $\kappa$-ET2Cu(NCS)2 single crystal on going through Tc(～10.4 K) and found no detectable effect during the superconducting phase transition.