Spin dynamics of a canted antiferromagnet in a magnetic field

Abstract

The spin dynamics of a canted antiferromagnet with a quadratic spin-wave dispersion near q =0 is shown to possess a unique signature. When the anisotropy gap is negligible, the spin-wave stiffness D sw ͑q , B͒ = ͑ q − B͒ / q 2 depends on whether the limit of zero field or zero wave vector is taken first. Consequently, D sw is a strong funtion of the magnetic field at a fixed wave vector. Even in the presence of a sizable anisotropy gap, the field dependence of the extrapolated q = 0 gap energy distinguishes a canted antiferromagnet from a phase-separated mixture containing both ferromagnetic and antiferromagnetic regions.

Spin rotation technique for non-collinear magnetic systems: application to the generalized Villain model

“…and the lattice constant a has been set to 1. In the limit k x = 0, ω k = B + 2γJS 1 ± cos (k y ) only depends on γJ, which is consistent with previous results [18,20,21,22]. As a function of γ, η, and k, the SF intensities are given by…”

“…To demonstrate this general technique, we investigate the generalized Villain model with an added interchain coupling. In recent years, the generalized Villain model (GVM) has been frequently used to test approaches to study magnetically frustrated systems and to help understand more complicated magnetic systems similar to those mentioned above [18,20,21,22]. In the GVM, chains of FM interactions J and AF interactions −ηJ along the x-axis are coupled together in the y direction by J [18,20,21,22], as illustrated in Fig.…”

Spin rotation technique for non-collinear magnetic systems: application to the generalized Villain model

“…Note that SC2 with α = π/2 is rotationally equivalent to SC1 with (0, π). study magnetically frustrated systems and to help understand more complicated magnetic systems similar to those mentioned above [18,20,21,22]. In the GVM, chains of FM interactions J and AF interactions −ηJ along the x-axis are coupled together in the y direction by J [18,20,21,22], as illustrated in Fig.…”

Phase diagram of strongly attractive p -orbital fermions on optical lattices

“…First, we rotate the spin operators σ 0 i into the local reference frame at each site using Euler rotation σ i = U i σ 0 i [here σ 0 i 's are the original spin operators in Eq. ( 4) and σ i 's are the spin operators in local reference frame], where the rotation matrix U i , is given by [53,54],…”