Role of exchange splitting and ligand-field splitting in tuning the magnetic anisotropy of an individual iridium atom on Ta S2 substrate

• Published in: Physical review. B 2021-06, Vol.103 (22), p.1
• Main Authors: Yan, Shiming, Qiao, Wen, Jin, Deyou, Xu, Xiaoyong, Mi, Wenbo, Wang, Dunhui
• Format: Article
• Language: English
• Subjects: Adatoms; Conservation; Exchanging; First principles; Iridium; Ligands; Magnetic anisotropy; Orbitals; Spin-orbit interactions; Splitting; Substrates; Transition metal compounds; Tuning
• ISSN: 2469-9950; 2469-9969
• DOI: 10.1103/PhysRevB.103.224432

In this work, using first-principles calculation we investigate the magnetic anisotropy (MA) of single-atom iridium (Ir) on Ta S2 substrate. We find that the strength and direction of MA in the Ir adatom can be tuned by strain. The MA arises from two sources, namely the spin-conservation term and the spin-flip term. The spin-conservation term is mainly generated by spin-orbit coupling (SOC) interaction on the dxy/dx2−y2 orbitals and is contributed to the out-of-plane MA. The spin-flip term is caused by SOC interaction on the dxz/dyz and px/py orbitals and is responsible for the in-plane MA. We further find that strain-tuned MA is mainly determined by exchange splitting and ligand-field splitting. Increase of strain will reduce the ligand-field splitting and enhance the exchange splitting, resulting in the enhancement of the out-of-plane MA from dxy/dx2 − y2 orbitals and the reduction of the in-plane MA from dxz/dyz and px/py orbitals, hence leading to the change of the strength and direction of the total MA. Our study provides a way for tuning the MA of a single-atom magnet on 2D transition metal dichalcogenide substrate by control of the exchange splitting and the ligand-field splitting.