Tuning the Kondo effect and quantum phase via side spin engineering in a high-spin molecular magnet

The single molecular magnet (SMM) has attracted significant interest recently due to its potential applications in quantum information processing and scalable quantum computing. Transport properties through the SMM is always dominated by quantum mechanics, among which the Kondo effect is one of the most vital issues. In this work, motivated by a recent work investigating exchange-induced spin polarization through a rare-earth porphyrin molecular complex (Tian Pei et al., 2022), we explore the Kondo effect in such an SMM affected by the intramolecular exchange coupling, magnetic anisotropy, and external magnetic field. It is demonstrated that the intramolecular exchange coupling suppresses the Kondo effect, with the ferromagnetic coupling exerting a stronger influence than the antiferromagnetic one. The longitudinal magnetic anisotropy also suppresses the Kondo behavior, and the transverse anisotropy has an opposite effect. An external magnetic field applied in the z -direction induces spin degeneracy breaking and total polarization in the charge occupation of the local conduction orbital, which also diminishes the conductivity through the SMM. To implement the above results, we adopt an expanded single impurity Anderson model and employ the state-of-the-art Wilson’s numerical renormalization group method. These insights are important for comprehending the potential applications of the SMM within the realms of quantum device and quantum information processing. • Kondo effect in a high-spin molecular magnet. • Kondo effect and quantum phase manipulated by a variety of factors. • Effect of the intramolecular exchange interaction and magnetic anisotropy. • Spin degeneracy breaking induced by the external magnetic field.