Spatially dependent f-π exchange interaction within a single-molecule magnet TbPc2
Xin Liao, Yun Chen, Tao Xie, Rui Sun, Lianzhi Yang, Chaofei Liu, Rui Wang, Svetlana Klyatskaya, Mario Ruben, Wenhao Zhang, Ying‐Shuang Fu
Abstract
Electrically probing the spin state of localized f electrons in a rare-earth-based single-molecule magnet, along with understanding its intramolecular magnetic coupling, is of crucial importance for applications in quantum information and advanced spintronics, yet it remains experimentally challenging. Herein, within a single-molecule magnet terbium(III) bis(phthalocyaninato) (TbPc2) double-decker molecule adsorbed on a bilayer graphene epitaxially grown on a SiC(0001) substrate, we experimentally demonstrate a spatially dependent exchange interaction between the magnetic moment of the localized Tb 4f electron and the unpaired spin of the Pc π-radical. The magnetic state of TbPc2, associated with the f-π interaction, is evidently detected through the spectroscopic Kondo resonance and a zero-field Kondo splitting, which can be reversibly switched in a charge/discharge process triggered by the tip-molecule distance. Furthermore, we theoretically describe how the Kondo resonance evolves at the molecular scale, which is mediated by the f-π exchange interaction with its strength varying spatially in a radial decay fashion. Our spatially resolved Kondo characteristics offer a quantitative understanding of the many-body spin correlation, which is coupled with the charge states in a nonuniform and spatially extended system. Detecting the localized nature of 4f orbitals in lanthanide ion is a major challenge. Here, the authors resolve the spatially dependent f-π exchange interaction within a single-molecule magnet TbPc2 and show their spin states can be electrically controlled in a reversible manner.