Regensburg 2004 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 47: Quantendr
ähte und Korrelationseffekte
HL 47.5: Vortrag
Freitag, 12. März 2004, 12:00–12:15, H15
Spin-charge separation in one-dimensional quantum dots: nonlinear transport and Negative Differential Conductance — •Fabio Cavaliere1,2, Alessandro Braggio2, Juergen Stockburger3, Maura Sassetti2 und Bernhard Kramer1 — 1I. Institut für Theoretische Physik, Universität Hamburg, Hamburg — 2Dipartimento di Fisica, INFM-Lamia, Università di Genova, Genova, Italy — 3II. Institut für Theoretische Physik, universität Stuttgart, Stuttgart
The study and control of the spin degree of freedom is nowadays the subject of many theoretical as well as experimental investigations. In few electrons quantum dots, the spin selection rules are considered the cause of the spin-blockade phenomenon [1] that leads to negative differential conductance (NDC). In the present work [2] we find that in 1D quantum dots the spin selection rules alone are not sufficient to give rise to NDC. On the contrary, in the framework of the Luttinger liquid theory we find that the separation of charge and spin degrees of freedom is responsible for the emergence of NDC in quantum dots with asymmetric barriers. The NDC phenomenon is related to the occupation of states with spin higher than the one in the ground state, therefore the effect of spin-flip relaxation processes is analyzed.
[1] D. Weinmann, et al. Phys. Rev. Lett 74, 984 (1995)
[2] F. Cavaliere et al. Submitted to Phys. Rev. Lett.