Abstract
The fundamental excitations in an antiferromagnetic chain of spins-1/2 are spinons, de-confined fractional quasiparticles that when combined in pairs, form a triplet excitation continuum. In an Ising-like spin chain the continuum is gapped and the ground state is Néel ordered. Here, we report high resolution neutron scattering experiments, which reveal how a magnetic field closes this gap and drives the spin chains in Yb 2 Pt 2 Pb to a critical, disordered Luttinger-liquid state. In Yb 2 Pt 2 Pb the effective spins-1/2 describe the dynamics of large, Ising-like Yb magnetic moments, ensuring that the measured excitations are exclusively longitudinal, which we find to be well described by time-dependent density matrix renormalization group calculations. The inter-chain coupling leads to the confinement of spinons, a condensed matter analog of quark confinement in quantum chromodynamics. Insensitive to transverse fluctuations, our measurements show how a gapless, dispersive longitudinal mode arises from confinement and evolves with magnetic order.
Original language | English |
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Article number | 1123 |
Journal | Nature Communications |
Volume | 10 |
Issue number | 1 |
DOIs | |
State | Published - Dec 1 2019 |
Bibliographical note
Funding Information:Work at Texas A&M University (W.J.G. and M.C.A) was supported by NSF-DMR-1310008. Work at Brookhaven National Laboratory (I.A.Z. and A.M.T.) was supported under the auspices of the US Department of Energy, Office of Basic Energy Sciences, under contract DE-SC00112704. Work at Northeastern University (A.E.F.) was supported by the US Department of Energy, Office of Science, Basic Energy Sciences grant number DE-SC0014407. Work at the ISIS neutron source was partly supported by the Science and Technology Facilities Council, STFC. Access to DCS was provided by the Center for High Resolution Neutron Scattering, a partnership between the National Institute of Standards and Technology and the National Science Foundation under Agreement No. DMR-1508249. We thank S.E. Nagler and R. Vega-Morales for helpful discussions about this work.
Publisher Copyright:
© 2019, The Author(s).
ASJC Scopus subject areas
- Chemistry (all)
- Biochemistry, Genetics and Molecular Biology (all)
- Physics and Astronomy (all)