Screening and transport in 2D semiconductor systems at low temperatures

Area of Science:

• Condensed matter physics
• Materials science
• Semiconductor physics

Background:

• Low-temperature carrier transport in 2D systems is limited by screened Coulomb disorder.
• RPA-Boltzmann theory describes scattering from charged impurities.

Purpose of the Study:

• Derive analytical formulas for intrinsic metallic temperature dependence in 2D transport.
• Explain the role of 2D screening properties in observed metallicity.
• Investigate why strong temperature dependence is sample-quality dependent and differs between materials.

Main Methods:

• Theoretical derivation of analytical formulas.
• Numerical calculations for density, mobility, and temperature ranges.
• Comparison of 2D and 3D screening functions.
• Analysis of interaction and disorder effects on screening.

Main Results:

• Identified conditions for strong intrinsic metallic temperature dependence in 2D transport.
• Explained the dependence of this effect on sample quality and material properties.
• Provided insights into why 3D systems do not exhibit similar intrinsic temperature dependence.
• Made experimentally verifiable predictions on low-temperature metallicity and quantum-classical crossover scaling.

Conclusions:

• 2D screening properties are crucial for intrinsic metallic temperature dependence in 2D transport.
• Sample quality and material-specific screening determine the magnitude of this effect.
• The absence of this strong intrinsic effect in 3D systems is linked to differences in screening functions.