| Record 1 of 8 |
| Author(s): Zhang, WC (Zhang, Wancheng); Wu, NJ (Wu, Nan-Jian) |
| Title: Compact non-binary fast adders using single-electron devices |
| Source: MICROELECTRONICS JOURNAL, 40 (8): 1244-1254 AUG 2009 |
| Abstract: This paper proposes compact adders that are based on non-binary redundant number systems and single-electron (SE) devices. The adders use the number of single electrons to represent discrete multiple-valued logic state and manipulate single electrons to perform arithmetic operations. These adders have fast speed and are referred as fast adders. We develop a family of SE transfer circuits based on MOSFET-based SE turnstile. The fast adder circuit can be easily designed by directly mapping the graphical counter tree diagram (CTD) representation of the addition algorithm to SE devices and circuits. We propose two design approaches to implement fast adders using SE transfer circuits: the threshold approach and the periodic approach. The periodic approach uses the voltage-controlled single-electron transfer characteristics to efficiently achieve periodic arithmetic functions. We use HSPICE simulator to verify fast adders operations. The speeds of the proposed adders are fast. The numbers of transistors of the adders are much smaller than conventional approaches. The power dissipations are much lower than CMOS and multiple-valued current-mode fast adders. (C) 2009 Elsevier Ltd. All rights reserved. |
| ISSN: 0026-2692 |
| DOI: 10.1016/j.mejo.2009.06.001 |
| Record 2 of 8 |
| Author(s): Tang, CG (Tang, C. G.); Chen, YH (Chen, Y. H.); Liu, Y (Liu, Y.); Wang, ZG (Wang, Z. G.) |
| Title: Anomalous-circular photogalvanic effect in a GaAs/AlGaAs two-dimensional electron gas |
| Source: JOURNAL OF PHYSICS-CONDENSED MATTER, 21 (37): Art. No. 375802 SEP 16 2009 |
| Abstract: We have studied the circular photogalvanic effect (CPGE) in a GaAs/AlGaAs two-dimensional electron gas excited by near infrared light at room temperature. The anomalous CPGE observed under normal incidence indicates a swirling current which is realized by a radial spin current via the reciprocal spin-Hall effect. The anomalous CPGE exhibits a cubic cosine dependence on the incidence angle, which is discussed in line with the above interpretation. |
| ISSN: 0953-8984 |
| Article Number: 375802 |
| DOI: 10.1088/0953-8984/21/37/375802 |
| Record 3 of 8 |
| Author(s): Luo, JY (Luo, Jun Yan); Jiao, HJ (Jiao, Hujun); Li, F (Li, Feng); Li, XQ (Li, Xin-Qi); Yan, YJ (Yan, Yi Jing) |
| Title: Reduced dynamics with renormalization in solid-state charge qubit measurement |
| Source: JOURNAL OF PHYSICS-CONDENSED MATTER, 21 (38): Art. No. 385801 SEP 23 2009 |
| Abstract: Quantum measurement will inevitably cause backaction on the measured system, resulting in the well-known dephasing and relaxation. In this paper, in the context of solid-state qubit measurement by a mesoscopic detector, we show that an alternative backaction known as renormalization is important under some circumstances. This effect is largely overlooked in the theory of quantum measurement. |
| ISSN: 0953-8984 |
| Article Number: 385801 |
| DOI: 10.1088/0953-8984/21/38/385801 |
| Record 4 of 8 |
| Author(s): Xu, DW (Xu, D. W.); Yoon, SF (Yoon, S. F.); Tong, CZ (Tong, C. Z.); Zhao, LJ (Zhao, L. J.); Ding, Y (Ding, Y.); Fan, WJ (Fan, W. J.) |
| Title: High-Temperature Continuous-Wave Single-Mode Operation of 1.3 mu m p-Doped InAs-GaAs Quantum-Dot VCSELs |
| Source: IEEE PHOTONICS TECHNOLOGY LETTERS, 21 (17): 1211-1213 SEP 1 2009 |
| Abstract: In this letter, we have demonstrated continuous-wave single-mode operation of 1.3-mu m InAs-GaAs quantum-dot (QD) vertical-cavity surface-emitting lasers (VCSELs) with p-type modulation-doped QD active region from 20 degrees C to 60 degrees C. The highest output power of 0.435mW and lowest threshold current of 1.2 mA under single-mode operation are achieved. The temperature-dependent output characteristics of QD-VCSELs are investigated. Single-mode operation with a sidemode suppression ratio of 34 dB is observed at room temperature. The critical size of oxide aperture for single-mode operation is discussed. |
| ISSN: 1041-1135 |
| DOI: 10.1109/LPT.2009.2024220 |
| Record 5 of 8 |
| Author(s): Liu, GH (Liu, G. H.); Chen, YH (Chen, Y. H.); Jia, CH (Jia, C. H.); Wang, ZG (Wang, Z. G.) |
| Title: Spin precession and electron spin polarization wave in [001]-grown quantum wells |
| Source: EUROPEAN PHYSICAL JOURNAL B, 70 (3): 397-401 AUG 2009 |
| Abstract: We theoretically study the spatial behaviors of spin precessions modulated by an effective magnetic field in a two-dimensional electron system with spin-orbit interaction. Through analysis of interaction between the spin and the effective magnetic field, we find some laws of spin precession in the system, by which we explain some previous phenomena of spin precession, and predict a controllable electron spin polarization wave in [001]-grown quantum wells. The shape of the wave, like water wave, mostly are ellipse-like or circle-like, and the wavelength is anisotropic in the quantum wells with two unequal coupling strengths of the Rashba and Dresselhaus interactions, and is isotropic in the quantum wells with only one spin orbit interaction. |
| ISSN: 1434-6028 |
| DOI: 10.1140/epjb/e2009-00237-9 |
| Record 6 of 8 |
| Author(s): Zhou, Y (Zhou, Yue); Zhang, GF (Zhang, Guo-Feng); Li, SS (Li, Shu-Shen); Abliz, A (Abliz, Ahmad) |
| Title: Optimal teleportation via thermal entangled states of a two-qubit Heisenberg chain |
| Source: EPL, 86 (5): Art. No. 50004 JUN 2009 |
| Abstract: We study the optimal teleportation based on Bell measurements via the thermal states of a two-qubit Heisenberg XXX chain in the presence of the Dzyaloshinsky-Moriya (DM) anisotropic antisymmetric interaction and obtain an optimal unitary transformation. The explicit expressions of the output state and the teleportation fidelity are presented and compared with those of the standard protocol. It is shown that in this protocol the teleportation fidelity is always larger and the unit fidelity is achieved at zero temperature. The DM interaction can enhance the teleportation fidelity at finite temperatures, as opposed to the effect of the interaction in the standard protocol. Cases with other types of anisotropies are also discussed. Copyright (C) EPLA, 2009 |
| ISSN: 0295-5075 |
| Article Number: 50004 |
| DOI: 10.1209/0295-5075/86/50004 |
| Record 7 of 8 |
| Author(s): Peng, WB (Peng Wen-Bo); Liu, SY (Liu Shi-Yong); Xiao, HB (Xiao Hai-Bo); Zhang, CS (Zhang Chang-Sha); Shi, MJ (Shi Ming-Ji); Zeng, XB (Zeng Xiang-Bo); Xu, YY (Xu Yan-Yue); Kong, GL (Kong Guang-Lin); Yu, YD (Yu Yu-De) |
| Title: Gap states and microstructure of microcrystalline silicon thin films |
| Source: ACTA PHYSICA SINICA, 58 (8): 5716-5720 AUG 2009 |
| Abstract: The density of states (DOS) above Fermi level of hydrogenated microcrystalline silicon (mu c-Si:H) films is correlated to the material microstructure. We use Raman scattering and infrared absorption spectra to characterize the structure of the films made with different hydrogen dilution ratios. The DOS of the films is examined by modulated photocurrent measurement. The results have been accounted for in the framework of a three-phase model comprised of amorphous and crystalline components, with the grain boundary as the third phase. We observed that the DOS increases monotonically as the grain boundary volume fractions f(gb) is increased, which indicates a positive correlation between the DOS and the grain boundary volume fraction. |
| ISSN: 1000-3290 |
| Record 8 of 8 |
| Author(s): Li, J (Li, Jing); Yang, YD (Yang, Yue-De); Huang, YZ (Huang, Yong-Zhen) |
| Title: Design of quantum cascade microcavity lasers based on Q factor versus etching depth |
| Source: JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 26 (8): 1484-1491 AUG 2009 |
| Abstract: The choice of the etching depth for semiconductor microcavities is a compromise between a high Q factor and a difficult technique in a practical fabricating process. In this paper, the influences of the etching depth on mode Q factors for mid-infrared quantum cascade microcylinder and microsquare lasers around 4.8 and 7.8 mu m are simulated by three-dimensional (3D) finite-difference time-domain (FDTD) techniques. For the microcylinder and the microsquare resonators, the mode Q factors of the whispering-gallery modes (WGMs) increase exponentially and linearly with the increase in the etching depth, respectively Furthermore, the mode Q factors of some higher order transverse WGMs may be larger than that of the fundamental transverse WGM in 3D microsquares. Based on the field distribution of the vertical multilayer slab waveguide and the mode Q factors versus the etching depth, the necessary etching depth is chosen at the position where the field amplitude is 1% of the peak value of the slab waveguide. In addition, the influences of sidewall roughness on the mode Q factors are simulated for microsquare resonators by 2D FDTD simulation. (C) 2009 Optical Society of America |
| ISSN: 0740-3224 |
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