Transcript Materials Computation Center R.M. Martin and J.P. Leburton

Materials Computation Center, University of Illinois
Duane D. Johnson and Richard Martin, NSF DMR-03-25939
Spintronics in Triple Quantum Dots
J.P. Leburton (ECE) and R.M. Martin (Physics)
Research
Objectives: Understand many-body effects in
semiconductor quantum dots (QDs) for applications
in quantum information processing.
Approach: We concentrate on material and
design parameters that influence the exchange
interaction between conduction electrons in realistic
double QDs. For this purpose, we use a combined
approach based on density functional theory (DFT)
to model the QD potential, and diffusion quantum
Monte Carlo to simulate accurately exchange and
correlation of electrons in the QD.
Significant Results: We investigate quantum
structures designed for three linearly coupled
vertical QDs made by lithography techniques
(artificial “molecules” in analogy with CO2 or NH2
linear molecules). DFT calculations unable us to
obtain the total energy of the system for a few
electrons, the single electron charging point (circles
on bottom left) and the stable spin configuration for
N=2-4 electrons (bottom right)
Broader Impact: Controlled device design
through science, and cross-disciplinary trained
students for industry.
MCC website: http://www.mcc.uiuc.edu
STM image of three linearly coupled QD device.
Left: Total energy for N-electrons; right: Spin configuration
x 10-3
N=1
N=2
N=3
N=4
J. Kim, P. Matagne, J.P. Leburton, R.M. Martin and S.
Tarucha “ Engineering Quantum Confinement and Orbital
Coupling in Laterally-Coupled Vertical Quantum Dots for
Spintronic Applications” IEEE Trans. Nanotechnol. (in
review)
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