Krane N, Turco E, Bernhardt A, Jacob D, Gandus G, Passerone D, Luisier M, Juríček M, Fasel R, Fernández-Rossier J, Ruffieux P
nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600 Dübendorf, Switzerland.
Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
Nano Lett. 2023 Oct 25;23(20):9353-9359. doi: 10.1021/acs.nanolett.3c02633. Epub 2023 Oct 11.
Phenalenyl is a radical nanographene with a triangular shape hosting an unpaired electron with spin = /. The open-shell nature of the phenalenyl is expected to be retained in covalently bonded networks. As a first step, we report synthesis of the phenalenyl dimer by combining in-solution synthesis and on-surface activation and its characterization on Au(111) and on a NaCl decoupling layer by means of inelastic electron tunneling spectroscopy (IETS). IETS shows inelastic steps that are identified as singlet-triplet excitation arising from interphenalenyl exchange. Spin excitation energies with and without the NaCl decoupling layer are 48 and 41 meV, respectively, indicating significant renormalization due to exchange with Au(111) electrons. Furthermore, third-neighbor hopping-induced interphenalenyl hybridization is fundamental to explaining the position-dependent bias asymmetry of the inelastic steps and activation of kinetic interphenalenyl exchange. Our results pave the way for bottom-up synthesis of = / spin-lattices with large exchange interactions.
菲萘基是一种呈三角形的自由基纳米石墨烯，其承载着一个自旋为1/2的未配对电子。预计菲萘基的开壳性质会在共价键网络中得以保留。作为第一步，我们报告了通过溶液内合成与表面活化相结合的方法合成菲萘基二聚体，并借助非弹性电子隧穿光谱（IETS）对其在Au(111)和NaCl解耦层上进行表征。IETS显示出非弹性台阶，这些台阶被确定为源于菲萘基间交换的单重态 - 三重态激发。有和没有NaCl解耦层时的自旋激发能量分别为48和41毫电子伏特，这表明由于与Au(111)电子的交换而产生了显著的重整化。此外，第三近邻跳跃诱导的菲萘基间杂化对于解释非弹性台阶的位置依赖性偏置不对称以及动力学菲萘基间交换的活化至关重要。我们的结果为具有大交换相互作用的1/2自旋晶格的自下而上合成铺平了道路。
