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arXiv 1002.3930cond-mat.mes-hall
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嵌入Aharonov-Bohm干涉仪中分子的输运性质

Transport properties of a molecule embedded in an Aharonov-Bohm interferometer

Jong Soo Lim, Rosa Lopez, Gloria Platero, Pascal Simon

摘要:

本文从理论上研究了嵌入介观Aharonov-Bohm干涉仪一臂中的分子的输运性质。由于声子的存在,分子能级位置($ε_d$)和电子-电子相互作用($U$)经历\emph{polaronic shift},其显著影响通过分子结的电子输运。当电子-声子相互作用较弱时,只要打开电极间的直接通道,线性电导呈现Fano线形。在线性电导中观察到的Fano共振是由自旋Kondo态与直接路径之间的干涉引起的,当电子-声子相互作用足够强时,电子-电子相互作用向负值重整化,{ \it,即}变得非常有吸引力。这种情况有利于空的和双占用的电荷状态之间的波动,因此促进了电荷近藤效应。然而,接触之间的直接路径破坏了电子-空穴对称性,这可以有效地抑制这种电荷近藤效应。然而,我们表明,适当的调整栅极电压是能够恢复近藤共振。我们的结果是用数值重整化近似计算电子谱函数和线性电导得到的。

英文摘要:

We theoretically investigate the transport properties of a molecule embedded in one arm of a mesoscopic Aharonov-Bohm interferometer. Due to the presence of phonons the molecule level position ($ε_d$) and the electron-electron interaction ($U$) undergo a \emph{polaronic shift} which affects dramatically the electronic transport through the molecular junction. When the electron-phonon interaction is weak the linear conductance presents Fano-line shapes as long as the direct channel between the electrodes is opened. The observed Fano resonances in the linear conductance are originated from the interference between the spin Kondo state and the direct path. For strong enough electron-phonon interaction, the electron-electron interaction is renormalized towards negative values, {\it i.e.} becomes effectively attractive. This scenario favors fluctuations between the empty and doubly occupied charge states and therefore promotes a charge Kondo effect. However, the direct path between the contacts breaks the electron-hole symmetry which can efficiently suppress this charge Kondo effect. Nevertheless, we show that a proper tuning of the gate voltage is able to revive the Kondo resonance. Our results are obtained by using the Numerical Renormalization approximation to compute the electronic spectral function and the linear conductance.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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