Tailoring the magnetism of 4f rare-earth atom lattices formed by metal-organic coordination

A single atom with long spin lifetime represents the prototype of the smallest bit for data storage. So far, single atom magnets have been obtained by adsorbing a 4f rare earth atom onto a well-defined site at surfaces, or by inserting it into custom-designed molecular frames. Here we propose a different approach. By combining atom adsorption at surfaces and 2D coordination with organic ligands, we aim at realizing a lattice of rare-earth single atom magnets with tunable magnetic properties. Coordination with tetraphenyl-dicarbonitrile molecules provides high-symmetry C5v crystal field, while the use of graphene as substrate minimizes spin-electron and spin-phonon scattering. The choice of the rare earth species, with oblate or prolate 4f charge distribution and different total angular moment J, determines the orientation of the magnetization easy axis and the spin lifetime.

具有长自旋寿命的单原子是数据存储领域最小比特的原型。迄今为止，单原子磁体的制备主要通过两种途径：将4f稀土原子吸附于表面的确定位点，或是将其嵌入定制设计的分子框架中。本文提出一种全新的技术路径：结合表面原子吸附与有机配体二维配位策略，以期构建具备可调谐磁学特性的稀土单原子磁体晶格。四苯基二腈（tetraphenyl-dicarbonitrile）分子配位可提供高对称性C5v晶体场，而以石墨烯作为衬底则可有效抑制自旋-电子与自旋-声子散射。稀土物种的选择，包括其扁球形或长球形的4f电荷分布以及各异的总角动量J，将决定易磁化轴的取向与自旋寿命。