Browsing by Author "Chen, C. D."

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Effect of the electromagnetic environment on the dynamics of charge and phase particles in one-dimensional arrays of small Josephson junctions
(2011-11-01)
Ho, I. L.
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Kuo, W.
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Lin, S. D.
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Lee, C. P.
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Liang, C. T.
The effect of the electromagnetic environment on the dynamics of quasi-particles, Cooper pairs and phase particles in one-dimensional arrays of small Josephson junctions is investigated experimentally and theoretically. It is found that the environment enhances the phase ordering and thus suppresses quasi-particle tunneling at high temperature and localization of Cooper pairs at low temperature. The dynamics is studied in the context of phase-charge duality, and the experimental results are quantitatively analyzed in both charge-ordered and phase-ordered regimes. Based on these analyses, a low-temperature phase diagram as well as a finite-temperature crossover phase diagram are constructed and compared to the experimental diagrams. Copyright (C) EPLA, 2011
Electrical and thermal transport in single nickel nanowire
(2008-02-11)
Ou, M. N.
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Yang, T. J.
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Harutyunyan, S. R.
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Chen, Y. Y.
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Chen, C. D.
The thermal conductivity and electrical resistivity of a suspended nickel nanowire have been measured for T=15-300 K. The temperature dependence of the thermal conductivity and the Lorenz number strongly differ from the bulk. The comparison of the transports in the Ni nanowire shows, that at temperatures 75 < T < 300 K Wiedemann-Franz (WF) law holds, whereas at temperatures T < 75 K the WF law is violated, indicating that thermal current in this material is suppressed more than electrical current. The results are explained by combined effect of confined dimension, enhanced disorder, and grown contribution of N-processes. (C) 2008 American Institute of Physics.
Thermal and electrical transport properties of a single nickel nanowire
(2007-12-01)
Ou, M. N.
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Harutyunyan, S. R.
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Lai, S. J.
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Chen, C. D.
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Yang, T. J.
The thermal conductivity (K), specific heat (C-p) and the resistivity (p) of a single nickel nanowire have been measured in the temperature range from 4 to 300 K by means of the "self heating 3 omega" technique. Starting with a 100 nm nickel film grown on a Si/Si3N4 substrate by thermal evaporation, a suspended nickel nanowire was then fabricated through e-beam lithography and etching processes. The width and length of the wire were determined by scanning electron microscope (SEM) as 180 nm and 35 mu m respectively. At 300 K the thermal conductivity of nanowire is similar to 20% of the bulk, it diminishes to lower value as temperature decreases. The consequence is opposite to that of the bulk and might be explained by the ristriction of mean free paths of electron/phonon-phonon interactions due to the grain boundaries. An enhancement of specific heat similar to 250% of the bulk is also observed. In addition, the resistivity of nanowire at room temperature is about four times larger than that of the bulk. The small relative resistiv-ity ratio (RRR) confirms the polycrystalline characteristic ofthe nanowire.