English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

A spin-orbital-entangled quantum liquid on a honeycomb lattice

MPS-Authors
/persons/resource/persons135493

Dinnebier,  R. E.
Scientific Facility X-Ray Diffraction (Robert E. Dinnebier), Max Planck Institute for Solid State Research, Max Planck Society;

/persons/resource/persons280580

Takagi,  H.
Department Quantum Materials (Hidenori Takagi), Max Planck Institute for Solid State Research, Max Planck Society;

External Resource
No external resources are shared
Fulltext (restricted access)
There are currently no full texts shared for your IP range.
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Kitagawa, K., Takayama, T., Matsumoto, Y., Kato, A., Takano, R., Kishimoto, Y., et al. (2018). A spin-orbital-entangled quantum liquid on a honeycomb lattice. Nature, 554(7692), 341-345.


Cite as: https://hdl.handle.net/21.11116/0000-000E-DF3E-3
Abstract
The honeycomb lattice is one of the simplest lattice structures. Electrons and spins on this simple lattice, however, often form exotic phases with non-trivial excitations. Massless Dirac fermions can emerge out of itinerant electrons, as demonstrated experimentally in graphene(1), and a topological quantum spin liquid with exotic quasiparticles can be realized in spin-1/2 magnets, as proposed theoretically in the Kitaev model(2). The quantum spin liquid is a long-sought exotic state of matter, in which interacting spins remain quantum-disordered without spontaneous symmetry breaking(3). The Kitaev model describes one example of a quantum spin liquid, and can be solved exactly by introducing two types of Majorana fermion(2). Realizing a Kitaev model in the laboratory, however, remains a challenge in materials science. Mott insulators with a honeycomb lattice of spin-orbital-entangled pseudospin-1/2 moments have been proposed(4), including the 5d-electron systems alpha-Na2IrO3 (ref. 5) and alpha-Li2IrO3 (ref. 6) and the 4d-electron system alpha-RuCl3 (ref.7). However, these candidates were found to magnetically order rather than form a liquid at sufficiently low temperatures(8-10), owing to non-Kitaev interactions(6,11-13). Here we report a quantum-liquid state of pseudospin-1/2 moments in the 5d-electron honeycomb compound H3LiIr2O6. This iridate does not display magnetic ordering down to 0.05 kelvin, despite an interaction energy of about 100 kelvin. We observe signatures of low-energy fermionic excitations that originate from a small number of spin defects in the nuclear-magnetic-resonance relaxation and the specific heat. We therefore conclude that H3LiIr2O6 is a quantum spin liquid. This result opens the door to finding exotic quasiparticles in a strongly spin-orbit-coupled 5d-electron transition-metal oxide.