Frustrated Ferromagnetic Spin Chains: A Variational Approach to Chirality Transitions

Thermal Excitations of Frustrated Xy Spins in Two Dimensions

We present a new variational approach to the study of phase transitions in frustrated 2D XY models. In the spirit of Villain’s approach for the ferromagnetic case we divide thermal excitations into a low temperature long wavelength part (LW) and a high temperature short wavelength part (SW). In the present work we mainly deal with LW excitations and we explicitly consider the cases of the fully...

Variational approach for uniformly frustrated 2D XY spin systems. I. Phase transitions in modulated arrays

Ground-State Phase Diagram of Frustrated Anisotropic Quantum Spin Chains

The low-energy properties of one-dimensional quantum spin systems with frustrating interactions have been studied extensively for many years. This is mainly because they exhibit a variety of ground-state phases accompanied with various types of spontaneous symmetry breaking, e.g., the dimer phase with the translational symmetry breaking. More recently novel phases have been found in the ground ...

Chirality Transitions in Frustrated S2 -valued Spin Systems

We study the discrete-to-continuum limit of the helical XY S -spin system on the lattice Z . We scale the interaction parameters in order to reduce the model to a spin chain in the vicinity of the Landau-Lifschitz point and we prove that at the same energy scaling under which the S -model presents scalar chirality transitions, the cost of every vectorial chirality transition is now zero. In add...

Large-S approach to chiral phases in frustrated spin chains

A large-S approach to the description of chiral phases in frustrated antiferromagnetic spin-S chains with easy-plane anisotropy is proposed. The approach is valid in the vicinity of the classical Lifshitz point j = 1 4 , where j is the relative strength of the frustrating next-nearest-neighbor coupling. The effective theory turns out to be the nonlinear σ-model with the additional fourth-order ...