Wang Xiaoli, Hou Dong, Zheng Xiao, Yan YiJing
Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Hefei National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui 230026, China.
J Chem Phys. 2016 Jan 21;144(3):034101. doi: 10.1063/1.4939843.
The magnetic anisotropy and Kondo phenomena in a mechanically stretched magnetic molecular junction are investigated by combining the density functional theory (DFT) and hierarchical equations of motion (HEOM) approach. The system is comprised of a magnetic complex Co(tpy-SH)2 sandwiched between adjacent gold electrodes, which is mechanically stretched in experiments done by Parks et al. [Science 328, 1370 (2010)]. The electronic structure and mechanical property of the stretched system are investigated via the DFT calculations. The HEOM approach is then employed to characterize the Kondo resonance features, based on the Anderson impurity model parameterized from the DFT results. It is confirmed that the ground state prefers the S = 1 local spin state. The structural properties, the magnetic anisotropy, and corresponding Kondo peak splitting in the axial stretching process are systematically evaluated. The results reveal that the strong electron correlations and the local magnetic properties of the molecule magnet are very sensitive to structural distortion. This work demonstrates that the combined DFT+HEOM approach could be useful in understanding and designing mechanically controlled molecular junctions.
通过结合密度泛函理论（DFT）和运动方程分层法（HEOM），研究了机械拉伸磁性分子结中的磁各向异性和近藤现象。该系统由夹在相邻金电极之间的磁性配合物Co(tpy-SH)2组成，在Parks等人[《科学》328, 1370 (2010)]所做的实验中对其进行了机械拉伸。通过DFT计算研究了拉伸系统的电子结构和力学性能。然后基于从DFT结果参数化的安德森杂质模型，采用HEOM方法来表征近藤共振特征。证实基态更倾向于S = 1的局域自旋态。系统地评估了轴向拉伸过程中的结构性质、磁各向异性以及相应的近藤峰分裂。结果表明，分子磁体的强电子关联和局域磁性质对结构畸变非常敏感。这项工作表明，DFT+HEOM组合方法在理解和设计机械控制分子结方面可能是有用的。
