Regensburg 2010 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 41: CE: Low-dimensional Systems - Models 2

TT 41.7: Talk

Friday, March 26, 2010, 12:00–12:15, H21

Pseudospin Resonance in two Coaxial Tubes — •Benedikt Scharf, Jaroslav Fabian, and Alex Matos-Abiague — Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Deutschland

In a 2DEG confined to two coaxial tubes the `tube degree of freedom' can be described in terms of pseudospin-1/2 dynamics. The presence of tunneling between the two tubes leads to a collective oscillation known as pseudospin resonance. We employ perturbation theory to examine the dependence of the frequency of this mode with respect to a coaxial magnetic field for the case of small intertube distances. Coulomb interaction leads to a shift of the resonance frequency and to a finite lifetime of the pseudospin excitations. Depending on the material the presence of the coaxial magnetic field can give rise to pronounced peaks in the shift of the resonance frequency. For very large magnetic fields this shift vanishes due to the effects of Zeeman splitting. Finally, an expression for the linewidth of the resonance is derived. Numerical analysis of this expression suggests that the linewidth strongly depends on the coaxial magnetic field, which leads to several peaks of the linewidth as well as regions where damping is almost completely suppressed. This work has been supported by the Deutsche Forschungsgemeinschaft via GRK 638 and GRK 1570.