Phase diagram of a frustrated mixed-spin ladder with diagonal exchange bonds

TL;DR

This study investigates how diagonal exchange bonds induce magnetic frustration in a mixed-spin ladder, revealing phase transitions from ferrimagnetic to spin-liquid states and identifying a critical partially-polarized ferromagnetic phase.

Contribution

It provides a detailed phase diagram of a frustrated mixed-spin ladder using numerical and conformal field theory methods, highlighting the effects of moderate frustrations.

Findings

Moderate frustrations destroy ferrimagnetic order.

A critical spin-liquid phase is stabilized.

A narrow partially-polarized ferromagnetic phase exists between phases.

Abstract

Using exact numerical diagonalization and the conformal field theory approach, we study the effect of magnetic frustrations due to diagonal exchange bonds in a system of two coupled mixed-spin $(1,{1/2})$ Heisenberg chains. It is established that relatively moderate frustrations are able to destroy the ferrimagnetic state and to stabilize the critical spin-liquid phase typical for half-integer-spin antiferromagnetic Heisenberg chains. Both phases are separated by a narrow but finite region occupied by a critical partially-polarized ferromagnetic phase.