A metamagnetic critical point in a three dimensional frustrated antiferromagnet

TL;DR

This paper investigates a three-dimensional frustrated antiferromagnet at a critical point, revealing a novel spin pseudogap state with a half-magnetization plateau but no long-range order, using Monte Carlo and low-temperature expansion methods.

Contribution

It introduces a new spin pseudogap state near a metamagnetic critical point in a 3D frustrated antiferromagnet, linking gap and pseudogap phenomena.

Findings

Identification of a half-magnetization plateau without long-range order.

Characterization of the spin pseudogap state using simulations and expansions.

Insights into the relationship between gap and pseudogap near criticality.

Abstract

The competition between different forms of order is central to the problem of strong correlation. This is particularly true of frustrated systems, which frequently exist at or near to a zero-temperature critical point. Here we show that a state with a half-magnetization plateau but no long range order can arise when a three dimensional frustrated antiferromagnet is tuned to a critical point bordering a metamagnetic state. We use classical Monte Carlo simulation and low-temperature expansion techniques to accurately characterize this `spin pseudogap' state, and show how its properties relate to those of the critical point. Our results provide an example of three dimensional spin model which can be used to study the relationship between gap and `pseudogap', - i.e. long range and preformed local order - near a metamagnetic critical point.