Spin State Manipulation of Nickel Quinonoid by Chemisorbed to a Co(001) Substrate

*Indukuru Ramesh Reddy (1), Peter M. Oppeneer (2), Kartick Tarafder (1)
(1) National Institute of Technology Karnataka, India, (2) Uppsala University, Sweden

We studied the structural, electronic and magnetic properties of recently synthesized Ni(II)-quinonoid molecule adsorb on magnetic Co(001) substrate by means of density functional theory (DFT)+U calculations. A strong covalent interaction at the interface increases the Ni-O(N) bond lengths in the chemisorbed molecule leads to a spin state switching in the molecule from S = 0 state (in the gas phase) to S ≈ 1 state upon adsorption on the Co(001) substrate. Our DFT+U calculations shows that the molecule is ferromagnetically coupled with substrate. The exchange mechanism between the Co surface and metal centre in the molecule (Ni atom) was carefully investigated. It has been found that an indirect exchange interaction via quinonid ligands of the molecule, stabilizes the spin moment in the molecule in ferromagnetic alignment with the Co surface magnetization.