Zhou Jian, Wang Qian, Sun Qiang, Kawazoe Yoshiyuki, Jena Puru
†Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China.
‡Center for Applied Physics and Technology, Peking University, Beijing 100871, China.
J Phys Chem Lett. 2012 Nov 1;3(21):3109-14. doi: 10.1021/jz301303t. Epub 2012 Oct 12.
Motivated by the recent success in synthesizing two-dimensional Fe-phthalocyanine (poly-FePc) porous sheets, we studied strain-induced spin crossover in poly-TMPc (TM = Mn, Fe, Co, and Ni) systems by using first-principle calculations based on density functional theory. A small amount of biaxial tensile strain is found to not only significantly enhance the magnetic moment of the central TM atoms by 2 μB when the strain reaches a critical value, but also the systems undergo low-spin (LS) to high-spin (HS) transition. These systems, however, show different response to strain, namely, poly-FePc sheet becomes ferromagnetic (FM) while poly-MnPc and poly-NiPc sheets become antiferromagnetic (AFM). Poly-CoPc, on the other hand, remains AFM. These predicted results can be observed in suspended poly-TMPc sheets by using scanning tunneling microscope (STM) tips to manipulate strain.
受近期合成二维铁酞菁（聚铁酞菁）多孔片成功的启发，我们基于密度泛函理论，利用第一性原理计算研究了聚四甲基酞菁（TM = Mn、Fe、Co和Ni）体系中应变诱导的自旋交叉现象。发现当应变达到临界值时，少量的双轴拉伸应变不仅能使中心TM原子的磁矩显著增强2 μB，而且体系会发生从低自旋（LS）到高自旋（HS）的转变。然而，这些体系对应变表现出不同的响应，即聚铁酞菁片变为铁磁性（FM），而聚锰酞菁和聚镍酞菁片变为反铁磁性（AFM）。另一方面，聚钴酞菁保持反铁磁性。通过使用扫描隧道显微镜（STM）针尖来操纵应变，可以在悬浮的聚四甲基酞菁片中观察到这些预测结果。
