Metallic low-temperature resistivity in a 2D electron system over an extended temperature range

Area of Science:

• Condensed matter physics
• Low-temperature physics

Background:

• Understanding electron behavior in two-dimensional (2D) systems is crucial for developing novel electronic devices.
• Previous studies on silicon-based 2D electron systems were limited to temperatures above 100 mK.

Purpose of the Study:

• To investigate the low-temperature electrical transport properties of a dilute 2D electron system in silicon.
• To explore the behavior of resistivity near the metal-insulator transition at unprecedentedly low temperatures.

Main Methods:

• Measurements of zero-field resistivity were conducted on a dilute 2D electron system in silicon.
• Experiments were performed at temperatures as low as 35 mK, extending the temperature range by nearly an order of magnitude.

Main Results:

• On the metallic side, resistivity continued to decrease with decreasing temperature, with no observed low-temperature upturn.
• At the critical electron density, resistivity remained constant across the entire measured temperature range (35 mK to 1 K).

Conclusions:

• The findings challenge existing theories regarding electron localization in 2D systems at very low temperatures.
• The temperature independence of resistivity at the critical density suggests a unique metallic state near the metal-insulator transition.