Molecular quantum magnetism in LiZn2Mo3O8

M Mourigal; W T Fuhrman; J P Sheckelton; A Wartelle; J A Rodriguez-Rivera; D L Abernathy; T M McQueen; C L Broholm

doi:10.1103/PhysRevLett.112.027202

Molecular quantum magnetism in LiZn2Mo3O8

Phys Rev Lett. 2014 Jan 17;112(2):027202. doi: 10.1103/PhysRevLett.112.027202. Epub 2014 Jan 15.

Authors

M Mourigal¹, W T Fuhrman¹, J P Sheckelton², A Wartelle³, J A Rodriguez-Rivera⁴, D L Abernathy⁵, T M McQueen², C L Broholm⁶

Affiliations

¹ Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA.
² Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA and Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, USA.
³ Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA and École Normale Supérieure de Lyon, Université de Lyon, 46 Allée d'Italie, 69364 Lyon Cedex 07, France.
⁴ NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA and Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA.
⁵ Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6475, USA.
⁶ Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA and NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA and Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6475, USA.

PMID: 24484043
DOI: 10.1103/PhysRevLett.112.027202

Abstract

Inelastic neutron scattering at low temperatures T≤30 K from a powder of LiZn2Mo3O8 demonstrates this triangular-lattice antiferromagnet hosts collective magnetic excitations from spin-1/2 Mo3O13 molecules. Apparently gapless (Δ<0.2 meV) and extending at least up to 2.5 meV, the low-energy magnetic scattering cross section is surprisingly broad in momentum space and involves one-third of the spins present above 100 K. The data are compatible with the presence of valence bonds involving nearest-neighbor and next-nearest-neighbor spins forming a disordered or dynamic state.