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.

6 pages, 7 eps figures, submitted to SNS 2001

References in corpus (4)

• Observation of two-magnon bound states in the two-leg ladders of (Ca,La)14Cu24O41
• Fractional and Integer Excitations in Quantum Antiferromagnetic Spin 1/2 Ladders
• Raman Response in Antiferromagnetic Two-Leg S=1/2 Heisenberg Ladders
• Multi-particle excitations and spectral densities in quantum spin-systems

Cited by in corpus (14)

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• The Structure of Operators in Effective Particle-Conserving Models
• Spectral Properties of Magnetic Excitations in Cuprate Two-Leg Ladder Systems
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• Optical study of orbital excitations in transition-metal oxides
• Revealing puddles of electrons and holes in compensated topological insulators
• Adapted continuous unitary transformation to treat systems with quasiparticles of finite lifetime
• Collective orbital excitations in orbitally ordered YVO3 and HoVO3
• Quantum criticality in the coupled two-leg spin ladder Ba2CuTeO6
• Jordan-Wigner approach to dynamic correlations in spin-ladders
• Multi-triplet bound states and finite-temperature dynamics in highly frustrated quantum spin ladders
• Electronic excitations in $5d^4$ J=0 Os${}^{4+}$ halides studied by RIXS and optical spectroscopy
• Optical absorption spectra in SrCu_2O_3 two-leg spin ladder
• Instantons and topological order in two-leg electron ladders: A universality class