Interfacial Spin Manipulation of Nickel-Quinonoid Complex Adsorbed on Co(001) Substrate

Abstract

We studied the structural, electronic, and magnetic properties of a recently synthesized Ni(II)-quinonoid complex upon adsorption on a magnetic Co(001) substrate. Our density functional theory + U (DFT+U) calculations predict that the molecule undergoes a spin-state switching from low-spin S = 0 in the gas phase to high-spin S ≈ 1 when adsorbed on the Co(001) surface. A strong covalent interaction of the quinonoid rings and surface atoms leads to an increase of the Ni–O(N) bond lengths in the chemisorbed molecule that support the spin-state switching. Our DFT+U calculations show that the molecule is ferromagnetically coupled to the substrate. The Co surface–Ni center exchange mechanism was carefully investigated. We identified an indirect exchange interaction via the quinonoid ligands that stabilizes the molecule’s spin moment in ferromagnetic alignment with the Co surface magnetization.

Theoretical Investigations of Electronic Structure and Magnetic and Optical Properties of Transition-Metal Dinuclear Molecules

“… 9 In one of our previous report, we have shown that the Ni-quinonoid molecule chemisorbed on the Co(100) surface, coupled ferromagnetically with the substrate, in which the Ni spin state switches from low spin (LS) to high spin (HS). 10 Several quinonoid-based organometallic compounds have been synthesized in the past few years, aiming to their application in spintronics. Kar et al 11 have recently reported quinonoid-based homo- and hetero-dinuclear complexes, where the two noble metals (Pt II and/or Pd II ) are linked through a quinonoid molecule.…”

“…Recently, a multifunctional Ni-quinonoid molecule has been reported in which a Ni atom connects two quinonoid molecules, exhibits a reversible color change, and undergoes structural transformation upon methanol adsorption . In one of our previous report, we have shown that the Ni-quinonoid molecule chemisorbed on the Co(100) surface, coupled ferromagnetically with the substrate, in which the Ni spin state switches from low spin (LS) to high spin (HS) . Several quinonoid-based organometallic compounds have been synthesized in the past few years, aiming to their application in spintronics.…”

Magnetic configurations of open-shell molecules on metals: The case of CuPc and CoPc on silver

“…An in-depth understanding of the electronic structure and magnetic properties of surface-adsorbed organic molecules is of direct relevance for and key to molecular spintronics [1][2][3][4][5][6][7][8][9][10][11]. Naturally, the deposition of nonmagnetic, closedshell molecules on magnetic substrates can result in a magnetic polarization of the molecule [12][13][14][15][16][17]. Conversely, for molecules which are already spin polarized in the gas phase, adsorption on a nonmagnetic surface can also result in interesting molecular magnetic properties, e.g., via charge-transfer processes from/towards the molecule and screening effects [16,[18][19][20][21].…”

“…Naturally, the deposition of nonmagnetic, closedshell molecules on magnetic substrates can result in a magnetic polarization of the molecule [12][13][14][15][16][17]. Conversely, for molecules which are already spin polarized in the gas phase, adsorption on a nonmagnetic surface can also result in interesting molecular magnetic properties, e.g., via charge-transfer processes from/towards the molecule and screening effects [16,[18][19][20][21]. The intrinsic magnetic moment of molecules is often quenched upon adsorption, especially in the case of strong hybridization [22][23][24].…”