Soliton binding and low-lying singlets in frustrated odd-legged S=1/2 spin tubes

TL;DR

This paper investigates the effects of frustration in odd-legged S=1/2 spin tubes, revealing that solitons can bind into low-lying singlets as the spin-chirality coupling diminishes, with implications for experimental systems.

Contribution

It derives an effective spin-chirality model for frustrated spin tubes with variable coupling and analyzes soliton binding and singlet formation using DMRG and analytical methods.

Findings

Spontaneous dimerization persists despite frustration.

Solitons become bound into low-lying singlets as coupling decreases.

Implications for experimental frustrated spin tube materials.

Abstract

Motivated by the intriguing properties of the vanadium spin tube Na2V3O7, we show that an effective spin-chirality model similar to that of standard Heisenberg odd-legged S=1/2 spin tubes can be derived for frustrated inter-ring couplings, but with a spin-chirality coupling constant alpha that can be arbitrarily small. Using density matrix renormalization group and analytical arguments, we show that, while spontaneous dimerization is always present, solitons become bound into low-lying singlets as alpha is reduced. Experimental implications for strongly frustrated tubes are discussed.