Probing the plateau-insulator quantum phase transition in the quantum hall regime

Area of Science:

• Condensed Matter Physics
• Quantum Phenomena
• Semiconductor Heterostructures

Background:

• Quantum Hall effect studies are crucial for understanding electron behavior in 2D systems.
• Plateau-insulator transitions in low-mobility heterostructures present complex physics.
• Existing research establishes critical exponents for plateau transitions, but universality classes require further investigation.

Purpose of the Study:

• To investigate the plateau-insulator transition in a low-mobility Indium Gallium Arsenide/Indium Phosphide heterostructure.
• To determine the critical exponent associated with this transition.
• To compare the universality class of plateau-insulator transitions with that of plateau-plateau transitions.

Main Methods:

• Quantum Hall effect measurements were performed on an In(0.53)Ga(0.47)As/InP heterostructure.
• Longitudinal resistance (rho(xx)) data were analyzed to identify exponential scaling laws.
• Inhomogeneity effects were corrected to analyze critical conductance (sigma(*)(xx)).

Main Results:

• Longitudinal resistance data followed an exponential law, yielding a critical exponent kappa = 0.55 ± 0.05.
• This exponent slightly differs from the established value of 0.42 ± 0.04 for plateau transitions.
• After correcting for inhomogeneity, critical conductance showed marginal temperature dependence.

Conclusions:

• The study indicates that plateau-plateau and plateau-insulator transitions in this system belong to the same universality class.
• The observed critical exponent suggests potential deviations from established theories or the influence of specific material properties.
• Further research is warranted to fully elucidate the universality of these transitions in low-mobility systems.