Probing temperature-driven flow lines in a gated two-dimensional electron gas with tunable spin-splitting

Area of Science:

• Condensed Matter Physics
• Semiconductor Nanostructures
• Quantum Phenomena

Background:

• Two-dimensional electron gases (2DEGs) in gallium arsenide (GaAs) are crucial for semiconductor device research.
• Self-assembled indium arsenide (InAs) quantum dots introduce unique electronic properties into GaAs 2DEGs.
• Understanding conductivity transitions is key to controlling electron behavior in nanostructures.

Purpose of the Study:

• To experimentally investigate the temperature dependence of conductivity in a gated GaAs 2DEG with InAs dots.
• To explore the influence of gate voltage on 2DEG density, disorder, and spin-splitting.
• To compare experimental results with theoretical predictions regarding phase transitions and critical Hall conductivity.

Main Methods:

• Fabrication of a gated GaAs 2DEG device incorporating self-assembled InAs dots.
• Temperature-dependent conductivity measurements.
• Tuning of 2DEG density and spin-splitting via gate voltage modulation.

Main Results:

• Observed temperature flow of conductivities in the gated GaAs 2DEG system.
• Demonstrated tuning of 2DEG density, disorder, and spin-splitting using gate voltage.
• Presented data on spin-resolved and spin-degenerate phase transitions, showing the former collapses into the latter under specific conditions.

Conclusions:

• Experimental results provide strong support for recent theoretical models based on modular symmetry.
• The study confirms theoretical predictions on the relationship between critical Hall conductivity and spin-splitting in such systems.
• Findings advance the understanding of electron transport and phase transitions in semiconductor nanostructures.