Hydrodynamic and Ballistic Transport over Large Length Scales in GaAs/AlGaAs

Area of Science:

• Condensed Matter Physics
• Mesoscopic Physics
• Semiconductor Heterostructures

Background:

• Understanding electron transport in two-dimensional electron systems (2DES) is crucial for developing advanced electronic devices.
• Distinguishing between hydrodynamic and ballistic transport regimes is essential for predicting device behavior.
• Previous studies often associated phenomena like negative nonlocal resistance and current vortices exclusively with the hydrodynamic regime.

Purpose of the Study:

• To investigate and compare hydrodynamic and ballistic transport regimes in a mesoscopic structure.
• To determine if collective transport phenomena, negative nonlocal resistances, and current vortices are exclusive to the hydrodynamic regime.
• To elucidate the critical factors influencing the demarcation of different transport regimes.

Main Methods:

• Utilized nonlocal resistance measurements on a high-mobility 2DES in a GaAs/AlGaAs heterostructure.
• Employed high-resolution kinetic simulations for detailed analysis.
• Performed one-to-one modeling of experimental devices to ensure accurate comparisons.

Main Results:

• Evinced the existence of collective transport phenomena in both hydrodynamic and ballistic transport regimes.
• Demonstrated that negative nonlocal resistances and current vortices are not exclusive to the hydrodynamic regime.
• Identified device design, measurement schemes, and accurate device modeling as critical for distinguishing transport regimes.

Conclusions:

• Collective transport phenomena are present in both hydrodynamic and ballistic transport regimes.
• Negative nonlocal resistances and current vortices can manifest in ballistic transport, broadening their known occurrence.
• Precise device design and accurate modeling are paramount for correctly identifying and understanding electron transport regimes in mesoscopic systems.