Canted antiferromagnetic phase in a double quantum well in a tilted quantizing magnetic field

TL;DR

This paper reports the discovery of a canted antiferromagnetic phase in a double quantum well system under a tilted magnetic field, revealing a new insulator-insulator quantum phase transition at filling factor 2.

Contribution

It provides experimental evidence for a canted antiferromagnetic phase in a double quantum well, demonstrating a novel quantum phase transition driven by magnetic field orientation.

Findings

Finite activation energy at the transition indicates a new insulator-insulator phase transition.

Observation of domain formation of two competing ground states.

Identification of a canted antiferromagnetic phase in the system.

Abstract

We investigate the double-layer electron system in a parabolic quantum well at filling factor $\nu=2$ in a tilted magnetic field using capacitance spectroscopy. The competition between two ground states is found at the Zeeman splitting appreciably smaller than the symmetric-antisymmetric splitting. Although at the transition point the system breaks up into domains of the two competing states, the activation energy turns out to be finite, signaling the occurrence of a new insulator-insulator quantum phase transition. We interpret the obtained results in terms of a predicted canted antiferromagnetic phase.