Localization-Delocalization Transition in Quantum Dots
N. B. Zhitenev,
1*
M. Brodsky,
1
R. C. Ashoori,
1
L. N. Pfeiffer,
2
K. W. West
2
Single-electron capacitance spectroscopy precisely measures the
energies required to add individual electrons to a quantum dot. The
spatial extent of electronic wave functions is probed by investigating
the dependence of these energies on changes in the dot confining
potential. For low electron densities, electrons occupy distinct
spatial sites localized within the dot. At higher densities, the
electrons become delocalized, and all wave functions are spread over
the full dot area. Near the delocalization transition, the last
remaining localized states exist at the perimeter of the dot.
Unexpectedly, these electrons appear to bind with electrons in the dot
center.
1 Department of Physics and Center for Materials
Science and Engineering, Massachusetts Institute of Technology,
Cambridge, MA 02139, USA.
2 Bell Laboratories, Lucent
Technologies, Murray Hill, NJ 07974, USA.
*
Present Address: Bell Laboratories, Lucent Technologies, Murray
Hill, NJ 07974, USA.
