Spinon confinement and a sharp longitudinal mode in Yb 2 Pt 2 Pb in magnetic fields

W. J. Gannon, I. A. Zaliznyak, L. S. Wu, A. E. Feiguin, A. M. Tsvelik, F. Demmel, Y. Qiu, J. R.D. Copley, M. S. Kim, M. C. Aronson

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


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 languageEnglish
Article number1123
JournalNature Communications
Issue number1
StatePublished - 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)


Dive into the research topics of 'Spinon confinement and a sharp longitudinal mode in Yb 2 Pt 2 Pb in magnetic fields'. Together they form a unique fingerprint.

Cite this