Nonequilibrium transport through molecular junctions in the quantum regime

0365033 - FZÚ 2012 RIV US eng J - Journal Article
Koch, T. - Loos, Jan - Alvermann, A. - Fehske, H.
Nonequilibrium transport through molecular junctions in the quantum regime.
Physical Review. B. Roč. 84, č. 12 (2011), 125131/1-125131/16. ISSN 1098-0121
Institutional research plan: CEZ:AV0Z10100521
Keywords : theory of electronic transport * scattering mechanisms * polarons and electron-phonon interactions * quantum dots
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 3.691, year: 2011

We consider a quantum dot, affected by a local vibrational mode and contacted to macroscopic leads, in the nonequilibrium steady-state regime. We apply a variational Lang-Firsov transformation and solve the equations of motion of the Green functions in the Kadanoff-Baym formalism up to a second order in the interaction coefficients. The variational determination of the transformation parameter through minimization of the thermodynamic potential allows us to calculate the electron/polaron spectral function and conductance for adiabatic to antiadiabatic phonon frequencies and weak to strong electron-phonon couplings. We investigate the qualitative impact of the quasiparticle renormalization on the inelastic electron tunneling spectroscopy signatures and discuss the possibility of a polaron induced negative differential conductance. In the high-voltage regime,we find that the polaron level follows the lead chemical potential to enhance resonant transport.
Permanent Link: http://hdl.handle.net/11104/0200373