Anyonic excitations emerging from a Kitaev spin liquid can form a basis for quantum computers. Searching for such excitations motivated intense research on the honeycomb iridate materials. However, access to a spin liquid ground state has been hindered by magnetic ordering. Cu2IrO3 is a new honeycomb iridate without thermodynamic signatures of a long-range order. Here, we use muon spin relaxation to uncover the magnetic ground state of Cu2IrO3. We find a two-component depolarization with slow and fast relaxation rates corresponding to distinct regions with dynamic and static magnetism, respectively. X-ray absorption spectroscopy and first principles calculations identify a mixed copper valence as the origin of this behavior. Our results suggest that a minority of Cu2+ ions nucleate regions of static magnetism whereas the majority of Cu+/Ir4+ on the honeycomb lattice give rise to a Kitaev spin liquid.
@article{arxiv.1811.00565,
title = {Competition between static and dynamic magnetism in the Kitaev spin liquid material Cu2IrO3},
author = {Eric M. Kenney and Carlo U. Segre and William Lafargue-Dit-Hauret and Oleg I. Lebedev and Mykola Abramchuk and Adam Berlie and Stephen P. Cottrell and Gediminas Simutis and Faranak Bahrami and Natalia E. Mordvinova and Jessica. L. McChesney and Gilberto Fabbris and Daniel Haskel and Xavier Rocquefelte and Michael J. Graf and Fazel Tafti},
journal= {arXiv preprint arXiv:1811.00565},
year = {2019}
}