title: Origin of the Spin-Orbital Liquid State in a Nearly J=0 Iridate Ba_{3}ZnIr_{2}O_{9}.
abstract: We show using detailed magnetic and thermodynamic studies and theoretical calculations that the ground state of Ba_{3}ZnIr_{2}O_{9} is a realization of a novel spin-orbital liquid state. Our results reveal that Ba_{3}ZnIr_{2}O_{9} with Ir^{5+} (5d^{4}) ions and strong spin-orbit coupling (SOC) arrives very close to the elusive J=0 state but each Ir ion still possesses a weak moment. Ab initio density functional calculations indicate that this moment is developed due to superexchange, mediated by a strong intradimer hopping mechanism. While the Ir spins within the structural Ir_{2}O_{9} dimer are expected to form a spin-orbit singlet state (SOS) with no resultant moment, substantial frustration arising from interdimer exchange interactions induce quantum fluctuations in these possible SOS states favoring a spin-orbital liquid phase down to at least 100 mK.
authors.affiliation: Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Nag
authors.affiliation: Centre for Advanced Materials, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
authors.forename: S
authors.initials: S
authors.lastname: Middey
authors.affiliation: Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
authors.forename: Sayantika
authors.initials: S
authors.lastname: Bhowal
authors.affiliation: Centre for Advanced Materials, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
authors.forename: S K
authors.initials: SK
authors.lastname: Panda
authors.affiliation: Department of Engineering Sciences, Uppsala University, P.O. Box 534, SE-751 21 Uppsala, Sweden.
authors.forename: Roland
authors.initials: R
authors.lastname: Mathieu
authors.affiliation: Laboratoire de Physique des Solides, UMR CNRS 8502, Université Paris-Sud, 91405 Orsay, France.
authors.forename: J C
authors.initials: JC
authors.lastname: Orain
authors.affiliation: Laboratoire de Physique des Solides, UMR CNRS 8502, Université Paris-Sud, 91405 Orsay, France.
authors.forename: F
authors.initials: F
authors.lastname: Bert
authors.affiliation: Laboratoire de Physique des Solides, UMR CNRS 8502, Université Paris-Sud, 91405 Orsay, France.
authors.forename: P
authors.initials: P
authors.lastname: Mendels
authors.affiliation: Laboratory for Quantum Magnetism (LQM), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland.|Jeremiah Horrocks Institute for Mathematics, Physics and Astrophysics, University of Central Lancashire, Preston PR1 2HE, United Kingdom.
authors.forename: P G
authors.initials: PG
authors.lastname: Freeman
authors.affiliation: Laboratory for Quantum Magnetism (LQM), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland.|Department of Materials and Nanophysics, KTH Royal Institute of Technology, Electrum 229, SE-16440 Kista, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Mansson
authors.affiliation: Laboratory for Quantum Magnetism (LQM), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland.
authors.forename: H M
authors.initials: HM
authors.lastname: Ronnow
authors.affiliation: ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX110QX, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Telling
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: P K
authors.initials: PK
authors.lastname: Biswas
authors.affiliation: Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Sheptyakov
authors.affiliation: UGC-DAE-Consortium for Scientific Research Mumbai Centre, R5 Shed, Bhabha Atomic Research Centre, Mumbai 400085, India.
authors.forename: S D
authors.initials: SD
authors.lastname: Kaushik
authors.affiliation: UGC-DAE-Consortium for Scientific Research Mumbai Centre, R5 Shed, Bhabha Atomic Research Centre, Mumbai 400085, India.
authors.forename: Vasudeva
authors.initials: V
authors.lastname: Siruguri
authors.affiliation: Dipartimento di Scienze, Universitá Roma Tre, Via della Vasca Navale, 84 I-00146 Roma, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Meneghini
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India.
authors.forename: D D
authors.initials: DD
authors.lastname: Sarma
authors.affiliation: Centre for Advanced Materials, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.|Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
authors.forename: Indra
authors.initials: I
authors.lastname: Dasgupta
authors.affiliation: Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.|Centre for Advanced Materials, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
authors.forename: Sugata
authors.initials: S
authors.lastname: Ray