Exact one- and two-particle excitation spectra of acute-angle helimagnets above their saturation magnetic field

Details Exact one- and two-particle excitation spectra of acute-angle helimagnets above their saturation magnetic field Exact one- and two-particle excitation spectra of acute-angle helimagnets above their saturation magnetic field

2006-10-28

arxiv.org/abs/cond-mat/0610801v1

Phys. Rev. B v. 75, 024401 (2007)

Physics

Condensed Matter

Strongly Correlated Electrons

21 pages, 6 Figures. submitted to Phys. Rev. B

Scientific paper

10.1103/PhysRevB.75.024401

The two-magnon problem for the frustrated XXZ spin-1/2 Heisenberg Hamiltonian and external magnetic fields exceeding the saturation field Bs is considered. We show that the problem can be exactly mapped onto an effective tight-binding impurity problem. It allows to obtain explicit exact expressions for the two-magnon Green's functions for arbitrary dimension and number of interactions. We apply this theory to a quasi-one dimensional helimagnet with ferromagnetic nearest neighbor J1 < 0 and antiferromagnetic next-nearest neighbor J2 > 0 interactions. An outstanding feature of the excitation spectrum is the existence of two-magnon bound states. This leads to deviations of the saturation field Bs from its classical value Bs(classical) which coincides with the one-magnon instability. For the refined frustration ratio |J2/J1|> 0.374661 the minimum of the two-magnon spectrum occurs at the boundary of the Brillouin zone. Based on the two-magnon approach, we propose general analytic expressions for the saturation field Bs, confirming known previous results for one-dimensional isotropic systems, but explore also the role of interchain and long-ranged intrachain interactions as well as of the exchange anisotropy.

Affiliated with

Also associated with

No associations

Rating

Exact one- and two-particle excitation spectra of acute-angle helimagnets above their saturation magnetic field does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Exact one- and two-particle excitation spectra of acute-angle helimagnets above their saturation magnetic field, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Exact one- and two-particle excitation spectra of acute-angle helimagnets above their saturation magnetic field will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-651592