Calculation of the current response in a nanojunction for an arbitrary time-dependent bias: application to the molecular wire

Progress in Non-equilibrium Green's Functions

Ridley, Michael^1,2 ; MacKinnon, Angus^2 ; Kantorovich, Lev^1

Department of Physics, King's College London, Strand-London

WC2R 2LS, United Kingdom^1

Department of Physics, Blackett Laboratory, Imperial College London, South Kensington Campus, London

SW7 2AZ, United Kingdom^2

关键词: Efficient numerical schemes;    Electron currents;    Electron transport;    Finite size effect;    Molecular junction;    One-dimensional molecular wires;    Single particle Hamiltonians;    Special functions;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/696/1/012017/pdf
DOI  :  10.1088/1742-6596/696/1/012017

来源: IOP

【 摘 要 】

Recently [Phys. Rev. B 91, 125433 (2015)] we derived a general formula for the time-dependent quantum electron current through a molecular junction subject to an arbitrary time-dependent bias within the Wide Band Limit Approximation (WBLA) and assuming a single particle Hamiltonian. Here we present an efficient numerical scheme for calculating the current and particle number. Using the Padé expansion of the Fermi function, it is shown that all frequency integrals occurring in the general formula for the current can be removed analytically. When the bias in the reservoirs is assumed to be sinusoidal it is possible to manipulate the general formula into a form containing only summations over special functions. To illustrate the method, we consider electron transport through a one-dimensional molecular wire coupled to two leads subject to out-of-phase biases. We also investigate finite size effects in the current response and particle number that result from the switch-on of this bias.