Ferrimagnetism in delta chain with anisotropic ferromagnetic and antiferromagnetic interactions

Abstract

We consider analytically and numerically an anisotropic spin-$\frac{1}{2}$ delta-chain (sawtooth chain) in which exchange interactions between apical and basal spins are ferromagnetic and those between basal spins are antiferromagnetic. In the limit of strong anisotropy of exchange interactions this model can be considered as the Ising delta chain with macroscopic degenerate ground state perturbed by transverse quantum fluctuations. These perturbations lift the ground state degeneracy and the model reduces to the basal XXZ spin chain in the magnetic field induced by static apical spins. We show that the ground state of such model is ferrimagnetic. The excitations of the model are formed by ferrimagnetic domains separated by domain walls with a finite energy. At low temperatures the system is effectively divided into two independent subsystems, the apical subsystem described by the Ising spin-$\frac{1}{2}$ chain and the basal subsystem described by the XXZ chain with infinite $zz$ interactions.

18 pages, 9 figures

References in corpus (3)

• Strongly correlated flat-band systems: The route from Heisenberg spins to Hubbard electrons
• Exact low-temperature behavior of kagome antiferromagnet at high fields
• Exact eigenstates and macroscopic magnetization jumps in strongly frustrated spin lattices

Cited by in corpus (11)

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• Electric field driven flat bands: Enhanced magnetoelectric and electrocaloric effects in frustrated quantum magnets
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• Two-dimensional spin models with macroscopic degeneracy
• Anomalous fractional quantization in the kagomelike Heisenberg ladder: Emergence of the effective spin-1 chain
• Macroscopic degeneracy of ground state in the frustrated Heisenberg diamond chain
• Magnetic properties of delta- and kagome-like chains with competing interactions
• Spin triangle chain with ferromagnetic and antiferromagnetic interactions on the transition line
• Magnetic properties of ferro-antiferromagnetic spin triangle chain
• On flat bands in the $J_1$-$J_2$-$J_3$ XXZ sawtooth chain