Gapped ground state in a spin-1/2 frustrated square lattice

TL;DR

This study investigates a spin-1/2 frustrated square lattice compound, revealing a gapped ground state linked to one-dimensional AF correlations and extending the spin-1 Haldane state concept to a 2D system.

Contribution

It introduces a model where frustration induces one-dimensionalization, leading to a gapped ground state and extending the Haldane state to two dimensions.

Findings

Magnetization curve shows gapped behavior.

Phase transition to an ordered state with 2D characteristics.

Gapped ground state arises from frustration-induced one-dimensionalization.

Abstract

We present a model compound with a spin-1/2 frustrated square lattice, in which three ferromagnetic (F) interactions and one antiferromagnetic (AF) compet. Considering the effective spin-1 formed by the dominant F dimer, this square lattice can be mapped to a spin-1 spatially anisotropic triangular lattice. The magnetization curve exhibits gapped behavior indicative of a dominant one-dimensional (1D) AF correlation. In the field-induced gapless phase, the specific heat and magnetic susceptibility show a phase transition to an ordered state with 2D characteristics. These results indicate that the spin-1 Haldane state is extended to the 2D system. We demonstrate that the gapped ground state observed in the present spin-1/2 frustrated square lattice originates from the one-dimensionalization caused by frustration.