Fourmental Cynthia, Mondal Sourav, Banerjee Rajdeep, Bellec Amandine, Garreau Yves, Coati Alessandro, Chacon Cyril, Girard Yann, Lagoute Jérôme, Rousset Sylvie, Boillot Marie-Laure, Mallah Talal, Enachescu Cristian, Barreteau Cyrille, Dappe Yannick J, Smogunov Alexander, Narasimhan Shobhana, Repain Vincent
Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France.
Theoretical Sciences Unit and School of Advanced Materials , Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur , Bangalore 560064 , India.
J Phys Chem Lett. 2019 Jul 18;10(14):4103-4109. doi: 10.1021/acs.jpclett.9b01303. Epub 2019 Jul 10.
Spin-crossover molecules are very appealing for use in multifunctional spintronic devices because of their ability to switch between high-spin and low-spin states with external stimuli such as voltage and light. In actual devices, the molecules are deposited on a substrate, which can modify their properties. However, surprisingly little is known about such molecule-substrate effects. Here we show for the first time, by grazing incidence X-ray diffraction, that an Fe spin-crossover molecular layer displays a well-defined epitaxial relationship with a metal substrate. Then we show, by both density functional calculations and a mechanoelastic model, that the resulting epitaxial strain and the related internal pressure can induce a partial spin conversion at low temperatures, which has indeed been observed experimentally. Our results emphasize the importance of substrate-induced spin state transitions and raise the possibility of exploiting them.
自旋交叉分子因其能够在电压和光等外部刺激下在高自旋态和低自旋态之间切换，而在多功能自旋电子器件中极具吸引力。在实际器件中，这些分子沉积在衬底上，这会改变它们的性质。然而，令人惊讶的是，人们对这种分子 - 衬底效应知之甚少。在这里，我们首次通过掠入射X射线衍射表明，铁自旋交叉分子层与金属衬底呈现出明确的外延关系。然后，我们通过密度泛函计算和机械弹性模型表明，由此产生的外延应变和相关的内压可在低温下诱导部分自旋转换，这确实已通过实验观察到。我们的结果强调了衬底诱导自旋态转变的重要性，并增加了利用它们的可能性。
