STM 分子结中电流非对称性的定性分析

doi:10.12066/j.issn.1007-2861.2028

Abstract

Abstract:

Quantum transport properties of molecular devices are mostly measured by scanning tunneling microscopy (STM). The results show abnormal features such as asymmetric I-V (AIV) curve or negative differential conductance (NDC), which are not to be observed in the case of common macroscopic devices. Based on finite element method and parameter models, the Hamiltonian of a sample system with a local state is presented. The non-equilibrium Green's function method is used to calculate the electron density and the tunneling current of the device after self-consistent convergence. After investigating the effects of different parameters, including the electrode coupling strength, molecular energy level, local energy level, the influences of the local states and geometrical asymmetry on the transport properties of molecular devices have been analyzed. It is concluded that the intrinsic region of AIV and NDC in STM related molecular devices experiments is the offset of the local states in the tip.

Key words: non-equilibrium Green's function, molecular device, quantum transport, density functional theory

CLC Number:

O469

QIAN Lijiang, LI Weiju, ZHANG Yibing, CHEN Jingzhe. Qualitative analysis of the asymmetric I-V curve in STM molecular junctions[J]. Journal of Shanghai University（Natural Science Edition）, 2020, 26(2): 197-206.

Figures/Tables 8

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References 18

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Qualitative analysis of the asymmetric I-V curve in STM molecular junctions

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