Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden.
J Phys Chem Lett. 2023 Mar 16;14(10):2558-2564. doi: 10.1021/acs.jpclett.3c00157. Epub 2023 Mar 6.
Magnetic phenomena in chemistry and condensed matter physics are considered to be associated with low temperatures. That a magnetic state or order is stable below a critical temperature as well as becoming stronger the lower the temperature is a nearly unquestioned paradigm. It is, therefore, surprising that recent experimental observations made on supramolecular aggregates suggest that, for instance, the magnetic coercivity may increase with an increasing temperature and the chiral-induced spin selectivity effect may be enhanced. Here, a mechanism for vibrationally stabilized magnetism is proposed, and a theoretical model is introduced with which the qualitative aspects of the recent experimental findings can be explained. It is argued that anharmonic vibrations, which become increasingly occupied with an increasing temperature, enable nuclear vibrations to both stabilize and sustain magnetic states. The theoretical proposal, hence, pertains to structures without inversion and/or reflection symmetries, for instance, chiral molecules and crystals.
化学和凝聚态物理中的磁现象被认为与低温有关。低温下稳定的磁态或有序,以及随着温度的降低而变得更强,这几乎是一个毋庸置疑的范例。因此,令人惊讶的是,最近对超分子聚集体的实验观察表明,例如,磁矫顽力可能随温度升高而增加,手性诱导自旋选择性效应可能增强。在这里,提出了一种振动稳定磁性的机制,并引入了一个理论模型,可以用该模型解释最近实验发现的定性方面。有人认为,随着温度的升高而越来越占据的非谐振动,使得核振动既能稳定又能维持磁态。因此,这一理论建议适用于没有反演和/或反射对称性的结构,例如手性分子和晶体。