Static and dynamical properties of elliptic quantum corrals
| Autor: | Nizama, M., Hallberg, K., Castro, J. d'Albuquerque e |
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| Rok vydání: | 2008 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 75 (2007) 235445 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.75.235445 |
| Popis: | Due to their focalizing properties, elliptic quantum corrals present very interesting physical behaviors. In this work, we analyze static and dynamical properties of these systems. Results are presented for realistic values of the parameters, which might be useful for comparison with experiments. We study noninteracting corrals and their response to several kinds of external perturbations, observing that, for realistic values of the Fermi level, the dynamics involves only a few number of excited states, making the system quite robust with respect to possible sources of decoherence. We also study the system in the presence of two S=1/2 impurities located at its foci, which interact with the electrons of the ellipse via a superexchange interaction J. This system is diagonalized numerically and properties such as the spin gap and spin-spin static and dynamical correlations are studied. We find that, for small J, both spins are locked in a singlet or triplet state, for even or odd filling, respectively, and its spin dynamics consists mainly of a single peak above the spin gap. In this limit, we can define an effective Heisenberg Hamiltonian to describe the low-energy properties. For larger J, more states are involved and the localized spins decorrelate in a manner similar to the Ruderman-Kittel-Kasuya-Yosida-Kondo transition for the two-impurity problem. Comment: 6 pages, 10 Encapsulated Postscript figures |
| Databáze: | arXiv |
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