Regensburg 2004 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 11: Nanoelektronik I: Quantenpunkte, -dr
ähte, -punktkontakte
TT 11.7: Vortrag
Dienstag, 9. März 2004, 11:00–11:15, H19
Nonlinear Transport through Quantum Wires: Functional Renormalization Group in Nonequilibrium — •Severin Jakobs1, Volker Meden2, Herbert Schoeller1, and Kurt Schönhammer2 — 1Institut für theoretische Physik A, RWTH Aachen, D-52056 Aachen, Germany — 2Institut für Theoretische Physik, Universität Göttingen, Bunsenstr. 9, D-37073 Göttingen, Germany
We study nonlinear transport at finite temperature through a quantum wire with impurities. The wire is modelled by a one-dimensional quantum lattice including nearest neighbour interaction. It is coupled via tunneling barriers to two reservoirs to which a finite bias voltage is applied. For calculating the nonequilibrium properties we generalize a functional renormalization group method (applied recently to the equilibrium case [1]) to the nonequilibrium situation by utilizing real-time Feynman diagrams. This enables us to handle weak as well as strong tunneling and arbitrary potentials on the wire. The coulomb interaction is treated within perturbative renormalization group, i.e. only the Hartree-Fock type of diagrams are included. For a single impurity in an infinite quantum wire we recover the exponents for the current vs. temperature and for the current vs. bias voltage predicted from bosonization [2]. For a finite wire however, the interplay of tunneling barriers and impurity produces exponents depending on the position of the impurity.
1ex [1] V. Meden et al., Phys. Rev. B 65, 045318 (2002)
C.L. Kane, M.P.A. Fisher, Phys. Rev. B 46, 15233 (1992)