title: Robust singlet dimers with fragile ordering in two-dimensional honeycomb lattice of Li2RuO3.
abstract: When an electronic system has strong correlations and a large spin-orbit interaction, it often exhibits a plethora of mutually competing quantum phases. How a particular quantum ground state is selected out of several possibilities is a very interesting question. However, equally fascinating is how such a quantum entangled state breaks up due to perturbation. This important question has relevance in very diverse fields of science from strongly correlated electron physics to quantum information. Here we report that a quantum entangled dimerized state or valence bond crystal (VBC) phase of Li2RuO3 shows nontrivial doping dependence as we perturb the Ru honeycomb lattice by replacing Ru with Li. Through extensive experimental studies, we demonstrate that the VBC phase melts into a valence bond liquid phase of the RVB (resonating valence bond) type. This system offers an interesting playground where one can test and refine our current understanding of the quantum competing phases in a single compound.
authors.affiliation: Center for Strongly Correlated Materials Research, Seoul National University, Seoul 08826, Korea.
authors.forename: Junghwan
authors.initials: J
authors.lastname: Park
authors.affiliation: Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Korea.
authors.forename: Teck-Yee
authors.initials: TY
authors.lastname: Tan
authors.affiliation: ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom.|Highly Correlated Matter Research Group, Physics Department, University of Johannesburg, Auckland Park 2006, South Africa.
authors.forename: D T
authors.initials: DT
authors.lastname: Adroja
authors.affiliation: ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Daoud-Aladine
authors.affiliation: Center for Strongly Correlated Materials Research, Seoul National University, Seoul 08826, Korea.|Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Korea.
authors.forename: Seongil
authors.initials: S
authors.lastname: Choi
authors.affiliation: Center for Strongly Correlated Materials Research, Seoul National University, Seoul 08826, Korea.|Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Korea.
authors.forename: Deok-Yong
authors.initials: DY
authors.lastname: Cho
authors.affiliation: Center for Strongly Correlated Materials Research, Seoul National University, Seoul 08826, Korea.|Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Korea.
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Center for Strongly Correlated Materials Research, Seoul National University, Seoul 08826, Korea.
authors.forename: Jiyeon
authors.initials: J
authors.lastname: Kim
authors.affiliation: Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Korea.|Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea.
authors.forename: Hasung
authors.initials: H
authors.lastname: Sim
authors.affiliation: Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Morioka
authors.affiliation: Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nojiri
authors.affiliation: Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030-4444, USA.
authors.forename: V V
authors.initials: VV
authors.lastname: Krishnamurthy
authors.affiliation: ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom.
authors.forename: P
authors.initials: P
authors.lastname: Manuel
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom.
authors.forename: M R
authors.initials: MR
authors.lastname: Lees
authors.affiliation: Institute of Metal Physics, Ekaterinburg 620041, Russia.|Department of Theoretical Physics and Applied Mathematics, Ural Federal University, Ekaterinburgh 620002, Russia.
authors.forename: S V
authors.initials: SV
authors.lastname: Streltsov
authors.affiliation: II Physikalisches Institut, University of Koeln, 50937 Koeln, Germany.
authors.forename: D I
authors.initials: DI
authors.lastname: Khomskii
authors.affiliation: Center for Strongly Correlated Materials Research, Seoul National University, Seoul 08826, Korea.|Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Korea.|Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea.
authors.forename: Je-Geun
authors.initials: JG
authors.lastname: Park