Interaction effects in conductivity of Si inversion layers at intermediate temperatures

Area of Science:

• Condensed Matter Physics
• Semiconductor Device Physics
• Mesoscopic Physics

Background:

• Understanding electron transport in semiconductor devices is crucial for electronic applications.
• The "metallic" state in such systems exhibits anomalous temperature-dependent resistivity.
• Recent theories propose interaction effects to explain these anomalies.

Purpose of the Study:

• To compare the temperature dependence of resistivity in Si-MOSFETs with recent theoretical predictions.
• To investigate the role of electron-electron interaction effects in the ballistic transport regime.
• To analyze the in-plane magnetoresistance and its consistency with theoretical models.

Main Methods:

• Fabrication and characterization of silicon metal-oxide-semiconductor field-effect transistors (Si-MOSFETs).
• Measurement of temperature dependence of resistivity (rho(T)).
• Measurement of in-plane magnetoresistance (rho(B(axially))).
• Determination of effective mass (m*) and g* factor from independent measurements.

Main Results:

• The anomalous increase of resistivity with temperature in Si-MOSFETs is quantitatively described by interaction effects in the ballistic regime.
• Effective mass and g* factor were determined independently.
• In-plane magnetoresistance showed only qualitative agreement with the theory.
• Quantitative discrepancies in magnetoresistance suggest higher sensitivity to sample-specific effects compared to resistivity.

Conclusions:

• Electron-electron interaction effects in the ballistic regime can explain the "metallic" behavior observed in Si-MOSFET resistivity.
• While resistivity measurements align well with theory, magnetoresistance is more susceptible to sample variations.
• Further refinement of theoretical models may be needed to fully capture magnetoresistance phenomena in these devices.