Quantitative Current鈥揤oltage Characteristics in Molecular Junctions from First Principles

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• 作者：Pierre Darancet ; Jonathan R. Widawsky ; Hyoung Joon Choi ; Latha Venkataraman ; Jeffrey B. Neaton
• 刊名：Nano Letters
• 出版年：2012
• 出版时间：December 12, 2012
• 年：2012
• 卷：12
• 期：12
• 页码：6250-6254
• 全文大小：373K
• 年卷期：v.12,no.12(December 12, 2012)
• ISSN：1530-6992

文摘

Using self-energy-corrected density functional theory (DFT) and a coherent scattering-state approach, we explain current鈥搗oltage (IV) measurements of four pyridine-Au and amine-Au linked molecular junctions with quantitative accuracy. Parameter-free many-electron self-energy corrections to DFT Kohn鈥揝ham eigenvalues are demonstrated to lead to excellent agreement with experiments at finite bias, improving upon order-of-magnitude errors in currents obtained with standard DFT approaches. We further propose an approximate route for prediction of quantitative IV characteristics for both symmetric and asymmetric molecular junctions based on linear response theory and knowledge of the Stark shifts of junction resonance energies. Our work demonstrates that a quantitative, computationally inexpensive description of coherent transport in molecular junctions is readily achievable, enabling new understanding and control of charge transport properties of molecular-scale interfaces at large bias voltages.

Keywords:

Density functional theory; many-body effects; current鈭抳oltage characteristics; Stark effect; molecular electronics; single molecule junction