Spin Disorder on a Triangular Lattice
Satoru Nakatsuji,1*
Yusuke Nambu,1
Hiroshi Tonomura,1
Osamu Sakai,1
Seth Jonas,3
Collin Broholm,3,4
Hirokazu Tsunetsugu,2
Yiming Qiu,4,5
Yoshiteru Maeno1,6
As liquids crystallize into solids on cooling, spins in magnets generally form periodic order. However, three decades ago, it was theoretically proposed that spins on a triangular lattice form a liquidlike disordered state at low temperatures. Whether or not a spin liquid is stabilized by geometrical frustration has remained an active point of inquiry ever since. Our thermodynamic and neutron measurements on NiGa2S4, a rare example of a two-dimensional triangular lattice antiferromagnet, demonstrate that geometrical frustration stabilizes a low-temperature spin-disordered state with coherence beyond the two-spin correlation length. Spin liquid formation may be an origin of such behavior.
1 Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
2 Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan.
3 Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA.
4 NIST Center for Neutron Research, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA.
5 Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA.
6 International Innovation Center, Kyoto University, Kyoto 606-8501, Japan.
* To whom correspondence should be addressed. E-mail: nakatsuji{at}scphys.kyoto-u.ac.jp
