Several Impurities in a Quantum Wire: Scaling of Conductance by Addition of Resistances?

Severin Jakobs

RWTH-Aachen

Severin Jakobs, Herbert Schoeller, Inst. für Theor. Physik A, RWTH Aachen,
Tilman Enss, Dipt. di Fisica, Universita di Roma "La Sapienza",
Volker Meden, Kurt Schönhammer, Inst. für Theor. Physik, Universität Göttingen
We analyze theoretically the conductance through an interacting quantum wire with several impurities, especially its dependence on temperature. The wire is modelled by a tight-binding-chain including nearest neighbour interaction. For calculating the transport properties we use a recently developed functional renormalization group method [1]. We find that three or more strong impurities divide the wire into a sequence of quantum dots whose resonace energies are in general incommensurable. This induces an irregular dependence of the total transmission on energy and temperature. The power laws predicted by bosonization for the current vs. temperature [2] are therefore eliminated in the presence of three or more impurities. However, the width of the single peaks of transmission is found to scale with temperature.
[1] V.Meden et al., Phys.Rev.B 65, 045318 (2002)
[2] C.L.Kane, M.P.A.Fisher, Phys.Rev.B 46, 15233 (1992)