Ligand Rotation Induced Oxidation State Change and Spin Appearance of the Bis(phthalocyaninato)cerium (CePc2) Molecule on the Au(111) Surface

Islam Saiful, Mohammad Ikram Hossain, Keiichi Katoh, Masahiro Yamashita, Ryuichi Arafune, Syed Mohammad Fakruddin Shahed, Tadahiro Komeda

Research output: Contribution to journalArticlepeer-review

Abstract

We demonstrate that a nonmagnetic molecule is changed into magnetic when its internal structure is rotated by forming an ordered film on a metal surface. We used a double-decker complex, bis(phthalocyaninato)cerium (CePc2), where the valence of the Ce atom changes between +3 and +4 with a small energy barrier. CePc2is nonmagnetic in bulk and becomes magnetic in the monolayer film on Au(111). The intra-molecular structure and the magnetic property are revealed using scanning tunneling microscopy/spectroscopy. We attribute the mechanism to a change of the rotational angle (θ) between the upper and lower Pc ligands, driven by the steric repulsive force originating from forming an almost square lattice on Au(111). The θ changes from θ = 45° of the bulk value into θ = 0° for the film. GGA + U calculation indicates that the change from θ = 45° to θ = 0° causes the Ce valence change from the nonmagnetic +4 state into the magnetic +3 state.

Original languageEnglish
Pages (from-to)17152-17163
Number of pages12
JournalJournal of Physical Chemistry C
Volume126
Issue number40
DOIs
Publication statusPublished - 2022 Oct 13

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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