Department of Chemistry and Center for Emerging Material and Advanced Devices and Center for Quantum Science and Engineering, National Taiwan University, Taipei 10617, Taiwan.
J Chem Phys. 2017 Apr 7;146(13):134113. doi: 10.1063/1.4979622.
We extend the quasi-particle renormalized perturbation theory developed in our previous work [Y.-W. Chang and B.-Y. Jin, J. Chem. Phys. 141, 064111 (2014)] based on nonequilibrium Green's function techniques to study the effects of electron correlation on the charge transport process in molecular junctions. In this formalism, the single-impurity Anderson's model is used as the zeroth-order Hamiltonian of each channel orbital, and the inter-channel interactions are treated by perturbation corrections. Within this scheme, the on-channel Coulomb repulsion and the single-particle spectral line-broadening can be incorporated in the zeroth-order approximation, and thus the Coulomb blockade and coherent tunneling through individual channels can be described properly. Beyond the zeroth-order description, electron correlation can be included through the self-energy corrections in the forms of the second-Born approximation and the GW approximation. The effects of electron correlation on molecular junctions are manifested as the orbital energy correction, correlated transport process, and collisional line-broadening. As an application, we have applied the present formalism to phenyl-based molecular junctions described by the Pariser-Parr-Pople Hamiltonian. The signatures of electron correlation in the simulated current-voltage curves are identified and discussed.
我们扩展了我们之前的工作[Y.-W. Chang 和 B.-Y. Jin，J. Chem. Phys. 141, 064111 (2014)]中基于非平衡格林函数技术的准粒子重整化微扰理论，以研究电子相关对分子结中电荷输运过程的影响。在这个形式体系中，单杂质安德森模型被用作每个通道轨道的零阶哈密顿量，而通道间相互作用则通过微扰修正来处理。在这个方案中，在零阶近似中可以包含通道内库仑排斥和单粒子谱线展宽，从而可以正确描述库仑阻塞和单个通道的相干隧穿。在零阶描述之外，可以通过第二 Born 近似和 GW 近似形式的自能修正来包含电子相关。电子相关对分子结的影响表现为轨道能量修正、相关输运过程和碰撞谱线展宽。作为应用，我们将这个形式体系应用于由 Pariser-Parr-Pople 哈密顿量描述的苯基分子结。识别并讨论了模拟电流-电压曲线中电子相关的特征。
