Magnetic Field Induced Exotic Phases in Isotropic Frustrated Spin-1/2 chain

TL;DR

This paper investigates the phase boundaries of exotic magnetic phases in a frustrated spin-1/2 chain under magnetic fields, using order parameters and numerical methods to provide direct evidence of phase existence.

Contribution

It introduces a direct method to determine phase boundaries in the $J_1-J_2$ model using order parameters and magnetization jumps, improving upon previous indirect approaches.

Findings

Vector chiral phase exists only in a narrow parameter range.

Strong magnetic fields break Z2 symmetry, affecting order parameter calculations.

Numerical methods confirm the limited stability of the vector chiral phase.

Abstract

The frustrated isotropic $J_1-J_2$ model with ferromagnetic $J_1$ and anti-ferromagnetic $J_2$ interactions in presence of an axial magnetic field shows many exotic phases, such as vector chiral and multipolar phases. The existing studies of the phase boundaries of these systems are based on the indirect evidences such as correlation functions {\it etc}. In this paper, the phase boundaries of these exotic phases are calculated based on order parameters and jumps in the magnetization. In the strong magnetic field, $Z_2$ symmetry is broken, therefore, order parameter of the vector chiral phase is calculated using the broken symmetry states. Our results obtained using the modified density matrix renormalization group and exact diagonalization methods, suggest that the vector chiral phase exist only in narrow range of parameter space $J_2/J_1$.