Formation of orbital molecules on a pyrochlore lattice induced by A-O bond covalency
Abstract
The pyrochlore ruthenate InRuO displays a subtle competition between spin-orbital entanglement and molecular orbital formation. At room temperature, a spin-orbit-entangled singlet state was identified. With decreasing temperature, InRuO undergoes multiple structural transitions and eventually forms a nonmagnetic ground state with semi-isolated RuO units on the pyrochlore lattice. The dominant hopping through the Ru-O-Ru linkage leads to molecular orbital formation within the RuO units. This molecular orbital formation is unique in that it involves the O anions, unlike the transition-metal dimers observed in systems with edge-sharing octahedra. We argue that the covalent character of In-O bonds plays a pivotal role in the structural transitions and molecular orbital formation and such bonding character of "-site" ions is an important ingredient for electronic phase competition in complex transition metal oxides.
Keywords
Cite
@article{arxiv.2111.05057,
title = {Formation of orbital molecules on a pyrochlore lattice induced by A-O bond covalency},
author = {A. Krajewska and A. Yaresko and J. Nuss and A. S. Gibbs and S. Bette and M. Blankenhorn and R. E. Dinnebier and D. P. Sari and I. Watanabe and J. Bertinshaw and H. Gretarsson and K. Ishii and D. Matsumura and T. Tsuji and M. Isobe and B. Keimer and H. Takagi and T. Takayama},
journal= {arXiv preprint arXiv:2111.05057},
year = {2021}
}