A variational coupled-cluster study of magnon-density-wave excitations in quantum antiferromagnets

Abstract

We extend recently proposed variational coupled-cluster method to describe excitation states of quantum antiferromagnetic bipartite lattices. We reproduce the spin-wave excitations (i.e., magnons with spin $\pm 1$). In addition, we obtain a new, spin-zero excitation (magnon-density waves) which has been missing in all existing spin-wave theories. Within our approximation, this magnon-density-wave excitation has a nonzero energy gap in a cubic lattice and is gapless in a square lattice, similar to those charge-density-wave excitations (plasmons) in quantum electron gases.

arXiv comment5 pages, 1 figure

References in corpus (4)

• Two-magnon excitations observed by neutron scattering in the two-dimensional spin-5/2 Heisenberg antiferromagnet Rb2MnF4
• Longitudinal magnetic excitations in classical spin systems
• Diagrammatic approach in the variational coupled-cluster method
• An extension of the coupled-cluster method: A variational formalism

Cited by in corpus (7)

• Longitudinal excitations in quantum antiferromagnets
• Excited states of quantum many-body interacting systems: A variational coupled-cluster description
• Longitudinal Excitations in Bipartite and Hexagonal Antiferromagnetic Spin Lattices
• A variational Jastrow coupled-cluster theory of quantum many-body systems
• Excited states of the quasi-one-dimensional hexagonal quantum antiferromagnets
• Longitudinal excitations in triangular lattice antiferromagnets
• The effects of three magnons interactions in the magnon-density waves of triangular spin lattices