Influence of vibrational modes on quantum transport through a nanodevice

Article

关键词: NUMERICAL RENORMALIZATION-GROUP;    NEGATIVE DIFFERENTIAL RESISTANCE;    STATES;   

DOI  :  10.1103/PhysRevB.87.195112

来源: SCIE

【 摘 要 】

We employ the recently proposed scattering states numerical renormalization group (SNRG) approach to calculate I (V) and the differential conductance through a single molecular level coupled to a local molecular phonon using the spinless Anderson-Holstein model. We also discuss the equilibrium physics of the model and demonstrate that the low-energy Hamiltonian is given by an effective interacting resonant level model. From the NRG level flow, we directly extract the effective charge transfer scale Gamma(eff) and the dynamically induced capacitive coupling U-eff between the molecular level and the lead electrons, which turns out to be proportional to the polaronic energy shift E-p for the regimes investigated here. The equilibrium spectral functions for the different parameter regimes are discussed. The additional phonon peaks at multiples of the phonon frequency omega(0) correspond to additional maxima in the differential conductance. Nonequilibrium effects, however, lead to significant deviations between a symmetric junction and a junction in the tunnel regime. The suppression of the current for particle-hole asymmetric junctions with increasing electron-phonon coupling, the hallmark of the Franck-Condon blockade, is discussed.

【 授权许可】

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