Two-magnon Raman scattering in spin-ladders with exact singlet-rung ground state

TL;DR

This paper introduces a family of spin-ladder models with an exact singlet-rung ground state, deriving an explicit formula for Raman scattering cross section and demonstrating good agreement with experimental data.

Contribution

It presents a new class of spin-ladder models with exact ground states and provides an explicit Raman scattering formula, advancing understanding of magnetic excitations.

Findings

Raman line-shapes are strongly asymmetric

Line-shapes have at most one van-Hove singularity

Results agree well with experimental observations

Abstract

We suggest a family of spin-ladder models with exact singlet-rung vacuum. In addition to the terms describing interactions along legs and rungs the Hamiltonian has frustration and cyclic terms. Using coordinate Bethe ansatze all one- and two-dimensional states are constructed. The explicit formula for zero-temperature Raman scattering cross section is derived. The corresponding line-shapes are strongly asymmetric and have no more than one van-Hove singularity. The results are in good agreement with experimental data.