Multiorbital antiferromagnetic metal induced by intramolecular self-doping

Abstract

The orbital of electrons in a solid affects their mutual interaction, which is a key to emergent phenomena. Therefore, control of the interplay between distinct orbitals makes the behavior of solids fertile. Such a case is substantiated by the aggregation of the molecule, M(tmdt)_{2}, which contains π orbitals extended over the organic ligand, tmdt, and a level-tunable d orbital centered at the metal ion M. Among them, Au(tmdt)_{2} exemplifies the critical π-d mixing, which arguably causes an over-100 K antiferromagnetic metal whose nature remains elusive. Here, we track the π-d interplay in Au(tmdt)_{2} with dual orbital-resolved probes, ^{13}C NMR and synchrotron x-ray diffraction. We find substantial intramolecular (interorbital) redistribution of electrons on cooling, triggering a commensurate π-d antiferromagnetic metal to emerge, which invokes an orbital-selective doped Mott insulator caused by intramolecular self-doping. This demonstrates that vital traffic of electrons between distinct orbitals brings about an unique correlated phase.