Estudo do acoplamento spin-órbita de multipartículas confinadas em pontos quânticos semicondutores

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Spin-orbit (SO) coupling provides a way for orbital degrees of freedom to influence spin states. As a result the spin dynamics is affected, thus making spin qubit (quantum version of bit, basic unit of information in the computational language) operations more complex. Furthermore, spin-orbit coupling leads to spin decoherence and relaxation due to phonons, thus limiting the operation time. Therefore, it is highly desirable to determine the parameters which govern the Spin-Orbit interaction so that one can control and manipulate the spin of particles. For the two electrons case, we observed the transition between spin polarized triplet and spin non-polarized singlet states. The spin-orbit interaction leads to an anticrossing between singlet and spin polarized triplet states, while the spin non-polarized triplet state remains unaffected. We also found that the Spin-Orbit interaction to be strongly dependent upon both the number of particles and their charge (positive or negative). For instance, the Spin-Orbit effect is much stronger for two electrons than for one exciton, which only induces the second order correction in the energy of the exciton. Furthermore, the filling of electronic shells of QD (closed and open shell configurations) can dramatically change the Spin-Orbit interaction leading to a competition with electron-electron interaction. Hence the Spin-Orbit interaction can be controlled electrically. We also analyzed the hyperfine interaction between bright and dark excitons.

ASSUNTO(S)

acoplamento spin-órbita Éxcitons quantum dots excitons pontos quânticos multielétrons Éxcitons carregados fisica spin-orbit coupling multielectrons charged excitons

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