Nano-Bio Spectroscopy Group and European Theoretical Spectroscopy Facility (ETSF), Departamento de Física de Materiales , Universidad del País Vasco UPV/EHU , Avenida Tolosa 72 , E-20018 San Sebastián , Spain.
IKERBASQUE, Basque Foundation for Science , María Díaz de Haro 3 , E-48013 Bilbao , Spain.
Nano Lett. 2018 Mar 14;18(3):2086-2090. doi: 10.1021/acs.nanolett.8b00255. Epub 2018 Feb 16.
We propose a scheme to extract the many-body spectral function of an interacting many-electron system from an equilibrium density functional theory (DFT) calculation. To this end we devise an ideal scanning tunneling microscope (STM) setup and employ the recently proposed steady-state DFT formalism (i-DFT) which allows one to calculate the steady current through a nanoscopic region coupled to two biased electrodes. In our setup, one of the electrodes serves as a probe ("STM tip"), which is weakly coupled to the system we want to measure. In the ideal STM limit of vanishing coupling to the tip, the system is restored to quasi-equilibrium and the normalized differential conductance yields the exact equilibrium many-body spectral function. Calculating this quantity from i-DFT, we derive an exact relation expressing the interacting spectral function in terms of the Kohn-Sham one. As illustrative examples, we apply our scheme to calculate the spectral functions of two nontrivial model systems, namely the single Anderson impurity model and the Constant Interaction Model.
我们提出了一种从相互作用多电子系统的平衡密度泛函理论（DFT）计算中提取多体谱函数的方案。为此，我们设计了一种理想的扫描隧道显微镜（STM）设置，并采用了最近提出的稳态 DFT 形式主义（i-DFT），该形式主义允许计算通过与两个偏置电极耦合的纳米区域的稳态电流。在我们的设置中，一个电极用作探针（“STM 尖端”），它与我们要测量的系统弱耦合。在尖端耦合趋于零的理想 STM 极限下，系统恢复到准平衡状态，归一化微分电导给出了精确的平衡多体谱函数。从 i-DFT 计算这个量，我们得出了一个精确的关系，用 Kohn-Sham 谱函数来表示相互作用谱函数。作为说明性示例，我们应用我们的方案来计算两个非平凡模型系统的谱函数，即单安德森杂质模型和常数相互作用模型。
