Transport in a Modulated One-Dimensional Ballistic Channel
Resource
CHINESE JOURNAL OF PHYSICS, VOL. 39, NO. 6
Journal
Chinese Journal of Physics
Journal Volume
VOL. 39
Journal Issue
NO. 6
Pages
-
Date Issued
2001-12
Date
2001-12
Author(s)
Liang, C.T.
Pepper, M.
Simmons, M.Y.
Smith, C.G.
Kim, Gil-Ho
Ritchie, D.A.
DOI
20060927115943539191
Abstract
In this paper we review measurements on a modulated one-dimensional (1D) ballistic
channel. We have designed a novel 1D channel with three separate and independently contacted
overlaying finger gates. By changing the applied voltages on the overlaying gate fingers,
we are able to vary the potential modulation in a ballistic 1D channel. Our experimental results
fall into two categories. (i) We show that “the 0.7 structure” [K. J. Thomas et al., Phys.
Rev. Lett. 77, 135 (1996)] persists despite a change of the lateral confinement strength by a
factor of 2. We have also shown that the 0.7 structure present in two 1D channels in series
behaves like a single 1D channel, demonstrating that the 0.7 structure is not a transmission
effect through a ballistic channel at zero in-plane magnetic field. (ii) In our versatile system,
an open quantum dot can be electrostatically defined by a split-gate, and two overlaying finger
gates which introduce entrance and exit barriers to the dot. In this case, we observe continuous
and periodic oscillations superimposed upon ballistic conductance steps at zero magnetic
field. We ascribe the observed conductance oscillations, when the conductance through the
dot G exceeds 2e2=h, to experimental evidence for Coulomb charging effects in an open dot
[C.-T. Liang et al., Phys. Rev. Lett. 81, 3507 (1998)]. This is supported by the evolution
of the oscillatory features for G > 2e2=h as a function of both temperature and barrier transparency.
Moreover, we present clear experimental evidence that coherent resonant transport
and Coulomb charging effects co-exist in our system.
Publisher
臺北市:國立臺灣大學物理系所
Type
journal article
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