Magnetic excitations in two-leg spin 1/2 ladders: experiment and theory
Abstract
Magnetic excitations in two-leg S=1/2 ladders are studied both experimentally and theoretically. Experimentally, we report on the reflectivity, the transmission and the optical conductivity sigma(omega) of undoped La_x Ca_14-x Cu_24 O_41 for x=4, 5, and 5.2. Using two different theoretical approaches (Jordan-Wigner fermions and perturbation theory), we calculate the dispersion of the elementary triplets, the optical conductivity and the momentum-resolved spectral density of two-triplet excitations for 0.2 <= J_parallel/J_perpendicular <= 1.2. We discuss phonon-assisted two-triplet absorption, the existence of two-triplet bound states, the two-triplet continuum, and the size of the exchange parameters.
Keywords
Cite
@article{arxiv.cond-mat/0109524,
title = {Magnetic excitations in two-leg spin 1/2 ladders: experiment and theory},
author = {M. Grueninger and M. Windt and T. Nunner and C. Knetter and K. P. Schmidt and G. S. Uhrig and T. Kopp and A. Freimuth and U. Ammerahl and B. Buechner and A. Revcolevschi},
journal= {arXiv preprint arXiv:cond-mat/0109524},
year = {2015}
}
Comments
6 pages, 7 eps figures, submitted to SNS 2001