title: Influence of Electron Correlation on the Electronic Structure and Magnetism of Transition-Metal Phthalocyanines.
abstract: There exists an extensive literature on the electronic structure of transition-metal phthalocyanines (TMPcs), either as single molecules or adsorbed on surfaces, where explicit intra-atomic Coulomb interactions of the strongly correlated orbitals are included in the form of a Hubbard U term. The choice of U is, to a large extent, based solely on previous values reported in the literature for similar systems. Here, we provide a systematic analysis of the influence of electron correlation on the electronic structure and magnetism of several TMPcs (MnPc, FePc, CoPc, NiPc, and CuPc). By comparing calculated results to valence-band photoelectron spectroscopy measurements, and by determining the Hubbard term from linear response, we show that the choice of U is not as straightforward and can be different for each different TMPc. This, in turn, highlights the importance of individually estimating the value of U for each system before performing any further analysis and shows how this value can influence the final results.
authors.affiliation: Department of Physics and Astronomy, Uppsala University , SE-75120 Uppsala, Sweden.
authors.forename: Iulia Emilia
authors.initials: IE
authors.lastname: Brumboiu
authors.affiliation: Department of Physics and Astronomy, Uppsala University , SE-75120 Uppsala, Sweden.
authors.forename: Soumyajyoti
authors.initials: S
authors.lastname: Haldar
authors.affiliation: Department of Physics and Astronomy, Uppsala University , SE-75120 Uppsala, Sweden.
authors.forename: Johann
authors.initials: J
authors.lastname: Lüder
authors.affiliation: Department of Physics and Astronomy, Uppsala University , SE-75120 Uppsala, Sweden.
authors.forename: Olle
authors.initials: O
authors.lastname: Eriksson
authors.affiliation: Department of Physics and Astronomy, Uppsala University , SE-75120 Uppsala, Sweden.
authors.forename: Heike C
authors.initials: HC
authors.lastname: Herper
authors.affiliation: Department of Physics and Astronomy, Uppsala University , SE-75120 Uppsala, Sweden.
authors.forename: Barbara
authors.initials: B
authors.lastname: Brena
authors.affiliation: Department of Physics and Astronomy, Uppsala University , SE-75120 Uppsala, Sweden.
authors.forename: Biplab
authors.initials: B
authors.lastname: Sanyal