A theoretical study of the quantum Wigner phase of electrons confined in semiconductor quantum dots (and related confined systems, e.g. rings and wires) will be performed.
The objectives of the project are:
- Determination of the mechanism for breakdown of the maximum density droplet and for the formation of the Wigner phase in quantum dots, quantum rings and wires. The aim is to solve the controversy between the proposed edge reconstruction and an intermediate stage of crystallization where a hole in the centre of the electron charge density appears;
- Study of the Wigner phase in systems with broken symmetry (and with anharmonic confinement). In this case the rotational invariance is broken and most of the available approaches fail to describe such systems;
- Study of the Wigner phase in large quantum dots with disorder induced by the local fluctuations of the confinement potential.
Phase diagrams for the quantum dot ground state will be constructed as function of the relevant parameters, e.g. magnetic field, confinement strength, anharmonicity and disorder. The theoretical results obtained during the realization of the project will be compared with the experimental data of transport and capacitance spectroscopy [e.g. Oosterkamp et al., Phys. Rev. Lett 82, 2931 (1999), Zhitenev et al, Phys. Rev. Lett. 79, 2308 (1997).
The project will be realized using the unrestricted Hartree-Fock method and a novel configuration interaction scheme with a multi-centre basis. This novel method of solution of the Schroedinger equation yields exact results in the high- magnetic field limit, in which the quantum system reproduces the classical configurations.
Furthermore, this approach is well suited to tackle systems with broken symmetry and disorder. The Antwerp research group is an international leading group in the study of the classical Wigner solid and the equivalent systems in confined geometries.
Fields of science
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