First-Order Phase Transitions in Frustrated Spin Systems

TL;DR

This paper reviews recent findings on first-order quantum phase transitions in frustrated spin chains, highlighting how varying exchange interactions and doping induce abrupt changes in magnetic and electronic properties.

Contribution

It provides a comprehensive overview of first-order phase transitions in frustrated spin systems, including effects of magnetic field and hole doping on phase behavior.

Findings

First-order transition between dimer and plaquette phases with discontinuous spin gap.

Magnetization plateaus and jumps induced by frustration in magnetic fields.

First-order metal-insulator transition triggered by hole doping.

Abstract

We give a short review of our recent works on the first-order quantum phase transitions in frustrated spin chains with orthogonal-dimer structure. When the ratio of the competing antiferromagnetic exchange couplings is varied, a first-order transition occurs between the dimer phase and the plaquette phase, which is accompanied by the discontinuity in the spin excitation gap. We further show that strong frustration triggers the phase transitions in a magnetic field, which exhibit plateaus and jumps in the magnetization curve. The hole-doping effect is also addressed for the orthogonal-dimer chain with linked-tetrahedra structure. It is found that the competing antiferromagnetic interactions result in a first-order metal-insulator transition upon hole doping.