Optical absorption of spin ladders
arXiv:cond-mat/9910322 · doi:10.1103/PhysRevB.61.14307
Abstract
We present a theory of phonon-assisted optical two-magnon absorption in two-leg spin-ladders. Based on the strong intra-rung-coupling limit we show that collective excitations of total spin S=0, 1 and 2 exist outside of the two-magnon continuum. It is demonstrated that the singlet collective state has a clear signature in the optical spectrum.
4 pages, 3 figures