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 NiGa
2S
4, 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.
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
