Phase transitions and spin dynamics of the quasi-one dimensional Ising-like antiferromagnet BaCo${}_2$V${}_2$O${}_8$ in a longitudinal magnetic field

Abstract

By combining inelastic neutron scattering and numerical simulations, we study the quasi-one dimensional Ising-like quantum antiferromagnet BaCo${}_2$V${}_2$O${}_8$ in a longitudinal magnetic field applied along the magnetic anisotropy axis, which is also the chain direction. The external field closes the excitation gap due to the magnetic anisotropy, inducing a transition from the Néel ordered state to an incommensurate longitudinal spin density wave phase. If the field is increased further, another transition into a transverse antiferromagnetic phase takes place at 9 T due to the competition between longitudinal and transverse correlations. We numerically and experimentally show that the model of XXZ chains connected by a weak interchain interaction well reproduces this transition. We also calculate the dynamical susceptibility and demonstrate that it agrees quantitatively with inelastic neutron scattering measurements. In contrast to the abrupt change of magnetic ordering, the spectra do not change much at the transition at 9 T, and the spin dynamics can be described as a Tomonaga-Luttinger liquid. We also refine the modeling of BaCo${}_2$V${}_2$O${}_8$ by including a four-site periodic term arising from the crystal structure which enables to account for an anomaly of the magnetic susceptibility appearing at 19 T as well as for the anticrossing observed in the inelastic neutron scattering spectra.

13 pages, 8 figures

References in corpus (4)

• Novel ordering of an S = 1/2 quasi one-dimensional Ising-like anitiferromagnet in magnetic field
• Longitudinal SDW order in a quasi-1D Ising-like quantum antiferromagnet
• Field-induced incommensurate order for the quasi-one-dimensional XXZ model in a magnetic field
• Tomonaga-Luttinger liquid spin dynamics in the quasi-one dimensional Ising-like antiferromagnet BaCo${}_2$V${}_2$O${}_8$

Cited by in corpus (4)

• Quantum phase transitions and composite excitations of antiferromagnetic spin trimer chains in a magnetic field
• Repulsively bound magnon excitations of a spin-1/2 XXZ chain in a staggered transverse field
• 1/5 and 1/3 magnetization plateaux in the spin 1/2 chain system YbAlO3
• Confinement of spinons in the XXZ spin-1/2 chain in presence of the transverse magnetic field