论文标题
用电子隧道光谱探测纳米仪中的局部矩
Probing local moments in nanographenes with electron tunneling spectroscopy
论文作者
论文摘要
理论上对石墨烯曲折边缘，晶界，空缺和SP3缺陷的局部力矩的出现进行了广泛的研究。但是，结论性的实验证据很少。地表合成的最新进展使得创建纳米仪，例如三角形，在其地面状态下，并使用扫描隧道显微镜（STM）光谱探测它们。在这里，我们回顾了顺序和共跨转运理论将DI/DV光谱与STM探测的纳米仪的自旋特性相关联。这种方法允许我们将DI/DV与石墨烯纳米结构的多体能量和波形连接。我们应用了这种方法，描述了纳米师的电子状态，通过在受限的活动空间内的哈伯德模型的对角线化。这使我们能够对石墨烯中当地矩的出现及其与运输的相互作用提供适当的量子描述。我们讨论了该理论的结果，在圆锥纳米仪的情况下，例如三角形，矩形丝带和CLAR Goblet，这些结构是通过STM光谱法实验研究的。这种方法允许我们同时计算DI/DV光谱，从而产生激发能以及原子解析的电导率图，这些图提供了有关集体旋转模式波形的信息。
The emergence of local moments in graphene zigzag edges, grain boundaries, vacancies and sp3 defects has been widely studied theoretically. However, conclusive experimental evidence is scarce. Recent progress in on-surface synthesis has made it possible to create nanographenes, such as triangulenes, with local moments in their ground states, and to probe them using scanning tunnelling microscope (STM) spectroscopy. Here we review the application of the theory of sequential and cotunneling transport to relate the dI/dV spectra with the spin properties of nanographenes probed by STM. This approach permits us to connect the dI/dV with the many-body energies and wavefunctions of the graphene nanostructures. We apply this method describing the electronic states of the nanographenes by means of exact diagonalization of the Hubbard model within a restricted Active Space. This permits us to provide a proper quantum description of the emergence of local moments in graphene and its interplay with transport. We discuss the results of this theory in the case of diradical nanographenes, such as triangulene, rectangular ribbons and the Clar goblet, that have been recently studied experimentally by means of STM spectroscopy. This approach permits us to calculate both the dI/dV spectra, that yields excitation energies, as well as the atomically resolved conductivity maps, that provide information on the wavefunctions of the collective spin modes.
