Composite Fermion States around 2D Hole Landau Level Filling Factor 3/2 in Tilted Magnetic Fields

TL;DR

This study investigates how tilted magnetic fields influence composite fermion states in 2D hole systems, revealing spin transitions and high-resistance phases linked to Landau level crossings driven by orbital effects.

Contribution

It provides new insights into spin polarization transitions and Landau level crossings in 2D hole systems under tilted magnetic fields, highlighting the role of orbital effects.

Findings

Partial to full spin polarization transition at ν=4/3

Emergence of high-resistance phase at ν=3/2 under high tilt angles

Landau level crossings driven mainly by orbital effects

Abstract

Transport measurements under a tilted magnetic field were performed on a series of C-doped (001) AlGaAs/GaAs/AlGaAs two-dimensional hole samples. Due to a large g-factor, Zeeman energy is large and comparable to the cyclotron energy in these samples. On the other hand, it was found that the in-plane component g// is small, and the effect of tilted magnetic field is mainly to increase the effective mass of holes. We investigate the spin transition of composite fermion states around Landau level (LL) filling factor 3/2. We found that the {\nu} = 4/3 state encounters a partial to full spin polarization transition, conforming to the same pattern as that of electron samples. In addition, high-resistance phase emerges at {\nu} = 3/2 under very high tilt angles. We interpret both of these phenomena as a consequence of LL crossings that are mainly driven by the orbital effects. The roles that the spin degrees of freedom play in FQH states around {\nu} = 3/2 in these systems will be discussed.