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Isospin Effect of the Pairing Correlation in Al Isotopes
ZHANG Hu-Yong, SHEN Wen-Qing, REN Zhong-Zhou, MA Yu-Gang, CAI Xiang-Zhou, ZHONG Chen, WEI Yi-Bin, CHEN Jin-Gen, ZHOU Xing-Fei, MA Guo-Liang, WANG Kun
Chin. Phys. Lett. 2003, 20 (1):
46-48
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The binding energies of Al isotopes are investigated by using the Skyrme-Hartree-Fock approach with the SKIII force parameter. Special emphasis is placed on the influence of the isospin effect of the pairing correlation on the neutron separation energy. Calculations show that the Skyrme-Hartree-Fock approach provides a good description of the binding energy of Al isotopes with different forms of pairing correlation. Meanwhile, it is found that the isospin effect of the pairing correlation plays a great role to the separation energy when the Al isotopes approach to the proton drip line.
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P-Type Doping of GaN by Mg+ Implantation
YAO Shu-De, ZHOU Sheng-Qiang, YANG Zi-Jian, LU Yi-Hong, SUN Chang-Chun, SUN Chang, ZHANG Guo-Yi, VANTOMME Andre, PIPELEERS Bert, ZHAO Qiang
Chin. Phys. Lett. 2003, 20 (1):
102-104
.
Mg+ and Mg+ + P+ were introduced into GaN by ion implantation. The structure and crystalline quality of the GaN samples were analysed by Rutherford backscattering and channeling spectrometry before (Xmin = 1.6%) and after implantation (Xmin = 4.1%). X-ray diffraction reveals the existence of implantation-induced damage in the case of post-implantation followed by rapid thermal annealing. The resistivity, average factor, carrier concentration and carrier mobility were measured by the Hall effect. The transformation from n-type to p-type for GaN was observed.
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Colossal Magnetoresistive p-n Junctions of Te-Doped LaMnO3/Nb-doped SrTiO3
LÜ, Hui-Bin, DAI Shou-Yu, CHEN Zheng-Hao, LIU Li-feng, GUO Hai-Zhong, XIANG Wen-Feng, FEI Yi-Yan, HE Meng, ZHOU Yue-Liang, YANG Guo-Zhen
Chin. Phys. Lett. 2003, 20 (1):
137-140
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We have fabricated colossal magnetoresistive (CMR) p-n junctions made of Te-doped LaMnO3 and Nb-doped SrTiO3 with laser molecular beam epitaxy. The I-V characteristics of the La0.9Te0.1MnO3/SrNb0.01Ti0.99O3 p-n junctions as a function of applied magnetic field (0-5 T) were experimentally studied in the temperature range 77-300 K. The results indicate that the p-n junction exhibited the CMR behaviour. The magnetoresistance (MR) is positive at 220 K and 300 K, while it displays a negative MR at 77 K. For a positive bias, the MR ratios (ΔR/R0, ΔR = RH-R0) are 7.5% at 0.1 T and 18% at 5 T for 300 K, 5% at 0.1 T and 33% at 5 T for 220 K, -14% at 0.1 T and -71% at 5 T for 77 K. For a negative bias, the MR ratios are 6.3% at 0.1 T and 10.8% at 3 T for 300 K, 5.1% at 0.T and 15% at 3 T for 220 K, -19% at 0.1 T and -72% at 5 T for 77 K. The CMR behaviour of the p-n junction is different from those of the LaMnO3 compound family.
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Switching Properties and Phase Transition Mechanism of Mo6+-Doped Vanadium Dioxide Thin Films
XU Shi-Qing, MA Hong-Ping, DAI Shi-Xun, JIANG Zhong-Hong
Chin. Phys. Lett. 2003, 20 (1):
148-150
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Using V2O5 and MoO3 powders as precursors, a novel preparation method, i.e., the so-called inorganic sol-gel, is developed to synthesize Mo6+-doped vanadium dioxide (VO2) thin films. The structure, valence state, phase transition temperature and magnitude of resistivity change are characterized by x-ray diffraction, x-ray photoelectron spectroscopy and the four point equipment. The results show that the main chemical composition of doped thin films was VO2, the structure of MoO3 in doped thin films did not change, and the phase transition temperature of doped thin films was obviously lowered with the increasing MoO3 doped concentration, but the magnitude of resistivity change was also decreased. However, so long as MoO3 doped concentration was not more than 5wt.%, the magnitude of resistivity change of doped thin films still reached more 2 orders. The analysis show that MoO3 dissolved in crystal structure of VO2 formed the donor defect MOxv and then reduced the forbidden-band width, which lowered the phase transition temperature. Consequently it was widened applications of the VO2 thin films.
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Structural and Dynamical Analysis of a Two-Dimensional Dusty Plasma Lattice
HUA Jian-Jun, LIU Yan-Hong, YE Mao-Fu, WANG Long, ZHANG Zhi-He
Chin. Phys. Lett. 2003, 20 (1):
155-157
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A two-dimensional dusty plasma lattice in an rf discharge was observed. The structural and dynamical properties were analysed by computing pair correlation function, static structure factor, bond-orientational correlation function and mean square displacement. The bond-orientational correlation function was found to fit into the law of r0.25, and the mean square displacement experienced “ballistic”, “subdiffusive” and “diffusive” regimes, both of which together with the other parameters indicate that the two dimensional dusty plasma stayed at a state between liquid and solid.
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52 articles
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