Correlation among particles in finite quantum systems leads to complex behaviour and novel states of matter. One remarkable example is predicted to occur in a semiconductor quantum dot(1-3), where at vanishing electron density the Coulomb interaction between electrons rigidly fixes their relative positions as those of the nuclei in a molecule(4-14). In this limit, the neutral few-body excitations are roto-vibrations, which have either rigid-rotor or relative-motion character(15). In the weak correlation regime, on the contrary, the Coriolis force mixes rotational and vibrational motions. Here, we report evidence for roto-vibrationalmodes of an electron molecular state at densities for which electron localization is not yet fully achieved. We probe these collective modes by using inelastic light scattering(16-18) in quantum dots containing four electrons(19). Spectra of low-lying excitations associated with changes of the relative-motion wavefunction-the analogues of the vibration modes of a conventional molecule-do not depend on the rotational state represented by the total angular momentum. Theoretical simulations by the configuration-interaction method(20) are in agreement with the observed roto-vibrational modes and indicate that such molecular excitations develop at the onset of short-range correlation.

A molecular state of correlated electrons in a quantum dot / S., Kalliakos; M., Rontani; V., Pellegrini; C. P., Garcia; A., Pinczuk; Goldoni, Guido; Molinari, Elisa; L. N., Pfeiffer; AND K. W., West. - In: NATURE PHYSICS. - ISSN 1745-2473. - STAMPA. - 4:(2008), pp. 467-471. [10.1038/nphys944]

A molecular state of correlated electrons in a quantum dot

GOLDONI, Guido;MOLINARI, Elisa;
2008

Abstract

Correlation among particles in finite quantum systems leads to complex behaviour and novel states of matter. One remarkable example is predicted to occur in a semiconductor quantum dot(1-3), where at vanishing electron density the Coulomb interaction between electrons rigidly fixes their relative positions as those of the nuclei in a molecule(4-14). In this limit, the neutral few-body excitations are roto-vibrations, which have either rigid-rotor or relative-motion character(15). In the weak correlation regime, on the contrary, the Coriolis force mixes rotational and vibrational motions. Here, we report evidence for roto-vibrationalmodes of an electron molecular state at densities for which electron localization is not yet fully achieved. We probe these collective modes by using inelastic light scattering(16-18) in quantum dots containing four electrons(19). Spectra of low-lying excitations associated with changes of the relative-motion wavefunction-the analogues of the vibration modes of a conventional molecule-do not depend on the rotational state represented by the total angular momentum. Theoretical simulations by the configuration-interaction method(20) are in agreement with the observed roto-vibrational modes and indicate that such molecular excitations develop at the onset of short-range correlation.
2008
4
467
471
A molecular state of correlated electrons in a quantum dot / S., Kalliakos; M., Rontani; V., Pellegrini; C. P., Garcia; A., Pinczuk; Goldoni, Guido; Molinari, Elisa; L. N., Pfeiffer; AND K. W., West. - In: NATURE PHYSICS. - ISSN 1745-2473. - STAMPA. - 4:(2008), pp. 467-471. [10.1038/nphys944]
S., Kalliakos; M., Rontani; V., Pellegrini; C. P., Garcia; A., Pinczuk; Goldoni, Guido; Molinari, Elisa; L. N., Pfeiffer; AND K. W., West
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/612920
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