Dependence on Density and Disorder of the Collective Localization along the ν=1 integer quantum Hall plateau*

The crossover between the Anderson insulator (AI) and the integer quantum Hall Wigner solid (IQHWS) within the integer quantum Hall regime remains poorly understood. The Anderson insulator forms at the center of the ν=1  plateau, while the Wigner solid develops in its flanks. Our measurements show that these two phases are consistently present in ultra-high-quality GaAs samples, which are grown using the latest state-of-the-art MBE techniques. I will discuss how the sample density, measured in the range of 0.42−1.0×10 ¹¹ cm⁻², influences the phase stability diagram. Interestingly, we find that the filling factor at the phase boundary between the integer quantum Hall Wigner solid and the Anderson insulator is almost independent of electron density. Additionally, I will explore the relationship between the phase boundary and residual disorder, as well as other properties of these two phases.