Field theoretical study of a spin-1/2 ladder with unequal chain exchanges

Abstract

We study the low-energy properties of a Heisenberg spin-1/2 zigzag ladder with different exchange constants on the two chains. Using a nonlinear sigma-model field theory and abelian bosonization, we find that the excitations are gapless, with a finite spin wave velocity, if the values of the chain exchanges are small. If the chain exchanges are large, the system is gapped, and the energy spectra of the kink and antikink excitations are different from each other.

Revtex, 4 pages, 1 eps figure

References in corpus (11)

• Surprises on the Way from 1D to 2D Quantum Magnets: the Novel Ladder Materials
• Bosonization and Strongly Correlated Systems
• Dimerization and Incommensurate Spiral Spin Correlations in the Zigzag Spin Chain: Analogies to the Kondo Lattice
• Numerical Evidence for Multiplicative Logarithmic Corrections from Marginal Operators
• Study of the magnetic susceptibility in the spin-Peierls system CuGeO${}_3$
• Elementary excitations in the $\Delta$-chain
• On Quantum Solitons in the Sawtooth Lattice
• Identification of Nuclear Relaxation Processes in a Gapped Quantum Magnet: Proton NMR in the S=1/2 Heisenberg Ladder Cu2(C5H12N2)2Cl4
• Phase diagram of an asymmetric spin ladder
• Non-linear Field Theory of a Frustrated Heisenberg Spin Chain
• Ordered phases in spin-Peierls systems

Cited by in corpus (9)

• Ground state and excitation of an asymmetric spin ladder model
• Enhancement of magnetization plateaus in low dimensional spin systems
• Ground State of a Heisenberg Chain with Next-Nearest-Neighbor Bond Alternation
• Interacting bosons in generalized zig-zag and railroad-trestle models
• Comment on "Phase Diagram of an Asymmetric Spin Ladder."
• Effective Hamiltonian for a Half-filled Hubbard Chain with Alternating On-site Interactions
• Ground-State Phase Diagram of the XXZ Model on a Railroad-Trestle Lattice with Asymmetric Leg Interactions
• Quantum spin pumping at fractionally quantized magnetization state for a system with competing exchange interactions
• Excitations of a low-dimensional dimerized spin ladder under a magnetic field