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TT: Tiefe Temperaturen

TT 11: Nanoelektronik I: Quantenpunkte, -dr
ähte, -punktkontakte

TT 11.5: Vortrag

Dienstag, 9. März 2004, 10:30–10:45, H19

Weak charge quantization and full current statistics — •Dmitry Bagrets¹ and Yuli Nazarov² — ¹Institut für Theoretische Festkörperphysik, Universität Karlsruhe, D-76128 Karlsruhe, Germany — ²Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands

We evaluate the full statistics of the current via a Coulomb island that is strongly coupled to the leads [1]. This strong coupling weakens the Coulomb interaction. We show that at voltages below the inverse RC-time in the circuit all effects of interaction can be incorporated into the energy renormalization of transmission eigenvalues of the arbitrary scatterers that connect the island and the leads. At moderate conductance G of the island below some critical value G_c the above renormalization results in the onset of an effective Coulomb blockade gap in the current-voltage dependence, the value of this gap being exponentially suppressed as compared to the classical charging energy E=e²/2C of the island. In the opposite case, G>G_c, the Coulomb blockade does not develop and the interaction correction to transport saturates at low voltages below the Thouless energy of the island. Remarkably, our renormalization group approach agrees with the previous equilibrium instanton calculations [2], i.e. both methods give the same energy scale for the effective charging energy.

[1] D.A. Bagrets and Yu. V. Nazarov, cond-matt/0304347

[2] Yuli V. Nazarov, Phys. Rev. Lett. 82, 1245 (1999).