Berlin 2008 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 35: Transport: Nanoelectronics I - Quantum Dots, Wires, Point Contacts 3

TT 35.12: Talk

Thursday, February 28, 2008, 17:15–17:30, H 3010

Critical conductance of a one-dimensional doped Mott insulator — •Markus Garst¹, Dmitry Novikov², Ady Stern³, and Leonid Glazman² — ¹Institut für Theoretische Physik, Universität zu Köln, 50938 Köln — ²Department of Physics, Yale University, New Haven, Connecticut 06520, USA — ³Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel

We consider the two-terminal conductance of a one-dimensional Mott insulator close to the commensurate-incommensurate quantum phase transition to a conducting state (arXiv:0708.0545). We treat the leads as Luttinger liquids. At a specific value of compressibility in the leads, corresponding to the Luther-Emery point, the conductance can be computed in terms of a scattering problem of non-interacting fermions with charge e/√2. The Mott insulator can be approximated as an effective point scatterer with a strongly energy dependent scattering matrix. At the Luther-Emery point, the temperature dependence of the conductance across the quantum phase transition is then described by a Fermi function. The deviation from the Luther-Emery point in the leads results in an interaction among the fermionic scattering states and changes the temperature dependence qualitatively. In the metallic state, the low-temperature conductance is determined by the properties of the leads, and is described by the conventional Luttinger liquid theory. In the insulating state, conductance still occurs via activation of e/√2 charges, and is independent of the Luttinger liquid compressibility.