Prudkovskiy Vladimir, Arbouch Imane, Léaustic Anne, Yu Pei, Van Dyck Colin, Guérin David, Lenfant Stéphane, Mallah Talal, Cornil Jérôme, Vuillaume Dominique
Institute for Electronics Microelectronics and Nanotechnology (IEMN), CNRS, Av. Poincaré, Villeneuve d'Ascq, France.
Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, 7000 Mons, Belgium.
Nanoscale. 2022 Apr 14;14(15):5725-5742. doi: 10.1039/d2nr00591c.
Two new photo-switchable terphenylthiazole molecules are synthesized and self-assembled as monolayers on Au and on ferromagnetic Co electrodes. The electron transport properties probed by conductive atomic force microscopy in ultra-high vacuum reveal a larger conductance of the light-induced closed (c) form than for the open (o) form. We report an unprecedented conductance ratio of up to 380 between the closed and open forms on Co for the molecule with the anchoring group (thiol) on the side of the two N atoms of the thiazole unit. This result is rationalized by Density Functional Theory (DFT) calculations coupled to the Non-Equilibrium Green's function (NEGF) formalism. These calculations show that the high conductance in the closed form is due to a strong electronic coupling between the terphenylthiazole molecules and the Co electrode that manifests by a resonant transmission peak at the Fermi energy of the Co electrode with a large broadening. This behavior is not observed for the same molecules self-assembled on gold electrodes. These high conductance ratios make these Co-based molecular junctions attractive candidates to develop and study switchable molecular spintronic devices.
合成了两种新型的光开关三联苯噻唑分子，并将它们在金电极和铁磁钴电极上自组装成单分子层。在超高真空下通过导电原子力显微镜探测的电子传输特性表明，光诱导的闭合（c）形式的电导率比开放（o）形式的电导率更大。对于噻唑单元两个N原子一侧带有锚定基团（硫醇）的分子，我们报道了在钴电极上闭合形式与开放形式之间前所未有的高达380的电导率比。通过结合非平衡格林函数（NEGF）形式的密度泛函理论（DFT）计算对该结果进行了合理化解释。这些计算表明，闭合形式下的高电导率是由于三联苯噻唑分子与钴电极之间的强电子耦合，这表现为在钴电极的费米能级处有一个具有大展宽的共振传输峰。在金电极上自组装的相同分子未观察到这种行为。这些高电导率比使得这些基于钴的分子结成为开发和研究可开关分子自旋电子器件的有吸引力的候选者。
