Gapped anisotropic spin chains in a field

Abstract

We consider the fully anisotropic Heisenberg spin-1/2 antiferromagnet in a uniform magnetic field, whose ground-state is characterized by broken spin rotation symmetry and gapped spinon excitations. We expand on a recent mean-field approach to the problem by incorporating fluctuations in a loop expansion. Quantitative results for the magnetization, excitation gap and specific heat are obtained. We compare our predictions with new DMRG and exact diagonalization data and, for zero field, with the exact solution of the XYZ spin chain from the Bethe Ansatz.

Spin ladder with anisotropic ferromagnetic legs in a transverse magnetic field

“…Due to the profound effect of quantum fluctuations the transverse magnetization remains small but finite for 0 < h ext < h ext c1 and reaches zero at h ext = 0. This is in agreement with results obtained within the weak-coupling continuum-limit bosonization treatment [29] and with the results for the magnetization obtained in the case of fully anisotropic XY Z chain [40]. For h ext > h ext c1 the magnetization increases linearly with increasing field once again in complete agreement with the predictions of bosonization analysis [29].…”

Dynamics of azurite Cu3(CO3)2(OH)Rule1, Tennant2, Caux3 et al. 2011Phys. Rev. B202220View full textAdd to dashboardCite

“…Although the spherical rotational symmetry is completely broken there is only one type of spinon which is now gapped. Within a mean field theory the particle and hole dispersions are given by 21 :…”

“…Here the transverse (left panels) and longitudinal (right panels) continua have been calculated for an anisotropic Heisenberg Hamiltonian, as defined in Equa- tion 1 from Ref. 21 , with applied fields increasing up to H z = 0.1. Here the saturation field along H z (equivalent to 11 T for azurite) is J x , J y and J z dependent.…”

Presaturation phase with no dipolar order in a quantum ferro-antiferromagnet

“…Incomplete polarization at high field could in principle stem from the small magnetic anisotropy present in the system [24,25]. However, this scenario can be excluded.…”