Ping-Yu Yang, L. Y. Wang, Yao-Wen Hsu, Juhn-Jong Lin
Magnetic field dependent universal conductance fluctuations (UCF's) are
observed in weakly disordered indium tin oxide nanowires from 0.26 K up to
$\sim 25$ K. The fluctuation magnitudes increase with decreasing temperature,
reaching a fraction of $e^2/h$ at $T \lesssim 1$ K. The shape of the UCF
patterns is found to be very sensitive to thermal cycling of the sample to room
temperatures, which induces irreversible impurity reconfigurations. On the
other hand, the UCF magnitudes are insensitive to thermal cycling. Our measured
temperature dependence of the root-mean-square UCF magnitudes are compared with
the existing theory [C. W. J. Beenakker and H. van Houten, Phys. Rev. B
\textbf{37}, 6544 (1988)]. A notable discrepancy is found, which seems to imply
that the experimental UCF's are not cut off by the thermal diffusion length
$L_T$, as would be expected by the theoretical prediction when $L_T <
L_\varphi$, where $L_\varphi$ is the electron dephasing length. The approximate
electron dephasing length is inferred from the UCF magnitudes and compared with
that extracted from the weak-localization magnetoresistance studies. A
reasonable semiquantitative agreement is observed.
View original:
http://arxiv.org/abs/1202.1329
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