Hund's rule in superatoms with transition metal impurities

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 108; no. 25; pp. 10062 - 10066
• Main Authors: Medel, Victor M, Reveles, Jose Ulises, Khanna, Shiv N, Chauhan, Vikas, Sen, Prasenjit, Castleman, A. Welford
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 21.06.2011; National Academy of Sciences Issue; National Acad Sciences
• Subjects: Atoms; Atoms & subatomic particles; Chemical valence; Crystal field theory; Electrons; Ground state; Magnetic dipole moment; magnetic fields; Metal clusters; Metals; Molecular orbitals; Orbitals; Physical Sciences; quantum dots; shape; transition elements; Transition metals
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1100129108

The quantum states in metal clusters bunch into supershells with associated orbitals having shapes resembling those in atoms, giving rise to the concept that selected clusters could mimic the characteristics of atoms and be classified as superatoms. Unlike atoms, the superatom orbitals span over multiple atoms and the filling of orbitals does not usually exhibit Hund's rule seen in atoms. Here, we demonstrate the possibility of enhancing exchange splitting in superatom shells via a composite cluster of a central transition metal and surrounding nearly free electron metal atoms. The transition metal d states hybridize with superatom D states and result in enhanced splitting between the majority and minority sets where the moment and the splitting can be controlled by the nature of the central atom. We demonstrate these findings through studies on TMMgn clusters where TM is a 3d atom. The clusters exhibit Hund's filling, opening the pathway to superatoms with magnetic shells.