• DOI:10.1038/s41467-019-08715-y
• Corpus ID: 71715553

Spinon confinement and a sharp longitudinal mode in Yb2Pt2Pb in magnetic fields

@article{Gannon2019SpinonCA,
  title={Spinon confinement and a sharp longitudinal mode in Yb2Pt2Pb in magnetic fields},
  author={William J.F. Gannon and Igor A. Zaliznyak and L. S. Wu and Adrian E. Feiguin and Alexei M. Tsvelik and Franz Demmel and Yiming Qiu and John R. D. Copley and M. S. Kim and Meigan C. Aronson},
  journal={Nature Communications},
  year={2019},
  volume={10}
}

• W. Gannon, I. Zaliznyak, +7 authors M. Aronson
• Published 8 March 2019
• Physics
• Nature Communications

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 Yb2Pt2Pb to a critical, disordered Luttinger-liquid state. In Yb2Pt2Pb 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.The behavior of quantum magnets depends strongly on the effective dimensionality of the inter-spin interactions. Here the authors tune the influence of two- and three-dimensional couplings in Yb2Pt2Pb with a magnetic field and hence control the behavior of emergent one-dimensional excitations.