Geometric, electronic and magnetic structure of Fe$_{x}$O$_{y}^{+}$ clusters

R. Logemann; G. A. de Wijs; M. I. Katsnelson; A. Kirilyuk

doi:10.1103/PhysRevB.92.144427

paper

Geometric, electronic and magnetic structure of Fe $_{x}$ O $_{y}^{+}$ clusters

arXiv:1506.02532 · doi:10.1103/PhysRevB.92.144427

Abstract

Correlation between geometry, electronic structure and magnetism of solids is both intriguing and elusive. This is particularly strongly manifested in small clusters, where a vast number of unusual structures appear. Here, we employ density functional theory in combination with a genetic search algorithm, GGA $+ U$ and a hybrid functional to determine the structure of gas phase Fe $_{x}$ O $_{y}^{+ /0}$ clusters. For Fe $_{x}$ O $_{y}$ cation clusters we also calculate the corresponding vibration spectra and compare them with experiments. We successfully identify Fe $_{3}$ O $_{4}^{+}$ , Fe $_{4}$ O $_{5}^{+}$ , Fe $_{4}$ O $_{6}^{+}$ , Fe $_{5}$ O $_{7}^{+}$ and propose structures for Fe $_{6}$ O $_{8}^{+}$ . Within the triangular geometric structure of Fe $_{3}$ O $_{4}^{+}$ a non-collinear, ferrimagnetic and ferromagnetic state are comparable in energy. Fe $_{4}$ O $_{5}^{+}$ and Fe $_{4}$ O $_{6}^{+}$ are ferrimagnetic with a residual magnetic moment of 1~\muB{} due to ionization. Fe $_{5}$ O $_{7}^{+}$ is ferrimagnetic due to the odd number of Fe atoms. We compare the electronic structure with bulk magnetite and find Fe $_{4}$ O $_{5}^{+}$ , Fe $_{4}$ O $_{6}^{+}$ , Fe $_{6}$ O $_{8}^{+}$ to be mixed valence clusters. In contrast, in Fe $_{3}$ O $_{4}^{+}$ and Fe $_{5}$ O $_{7}^{+}$ all Fe are found to be trivalent.

14 pages, 21 figures

Geometric, electronic and magnetic structure of Fe $_{x}$ O $_{y}^{+}$ clusters

Abstract

References in corpus (3)

Cited by in corpus (4)

Geometric, electronic and magnetic structure of Fex​Oy+​ clusters

Abstract

References in corpus (3)

Cited by in corpus (4)

Geometric, electronic and magnetic structure of Fe $_{x}$ O $_{y}^{+}$ clusters