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

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 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. Th

SUBMITTER: Gannon WJ 

PROVIDER: S-EPMC6408591 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature