Effect of in-plane magnetic field on magnetic phase transitions in nu=2 bilayer quantum Hall systems

TL;DR

This paper investigates how an in-plane magnetic field influences magnetic phase transitions in bilayer quantum Hall systems at filling factor nu=2, revealing that tilting the magnetic field can induce phase changes and identifying a universal critical exponent.

Contribution

The study applies an effective bosonic spin theory to analyze magnetic phase transitions under tilted magnetic fields, providing new insights into phase diagram modifications and critical behavior.

Findings

Quantum phase diagram is altered by in-plane magnetic field.

Quantum phase transitions can be induced by tilting the magnetic field.

Universal critical exponent for phase transition is 1/2.

Abstract

By using the effective bosonic spin theory, which is recently proposed by Demler and Das Sarma [ Phys. Rev. Lett. 82, 3895 (1999) ], we analyze the effect of an external in-plane magnetic field on the magnetic phase transitions of the bilayer quantum Hall system at filling factor nu=2. It is found that the quantum phase diagram is modified by the in-plane magnetic field. Therefore, quantum phase transitions can be induced simply by tilting the magnetic field. The general behavior of the critical tilted angle for different layer separations and interlayer tunneling amplitudes is shown. We find that the critical tilted angles being calculated agree very well with the reported values. Moreover, a universal critical exponent for the transition from the canted antiferromagnetic phase to the ferromagnetic phase is found to be equal to 1/2 within the present effective theory.