Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 37: Transport - Fluctuations and Noise
TT 37.2: Vortrag
Mittwoch, 9. März 2005, 10:30–10:45, TU H3027
Statistics of Current Fluctuations and Coulomb Interaction in Diffusive Conductors — •Dmitry Bagrets — Institut für Theoretische Festkörperphysik, Universität Karlsruhe, 76128 Karlsruhe.
I evaluate the full current statistics (FCS) in the low dimensional (1D and 2D) diffusive conductors in the incoherent regime, eV ≫ 1/τD, τD being the diffusion time through the conductor[1]. It is shown that Coulomb interaction substantially enhances the probability of big current fluctuations for short conductors with τD ≪ τE, τE being the voltage dependent energy relaxation time, leading to the exponential tails in the current distribution. These tails arise from the huge fluctuations of the current of electron-hole pairs which are excited by the low frequency classical fluctuations of the electromagnetic field in the system. The current fluctuations are most strong for temperatures below 1/τD, provided τD ∼ τ*(V), where the time scale τ*(V) is parametrically smaller than the energy relaxation time τE(V). Remarkably, the time τ*(V) transforms to the decoherence time τϕ(T), known from the theory of weak localization[2], if one substitutes voltage for the temperature.
[1] D. A. Bagrets, cond-mat/0406483, to appear in Phys. Rev. Lett.
[2] B.L. Altshuler, A.G. Aronov and D.E. Khmelnitsky, J.Phys. C 15 7367 (1982)