Mechanical Control of Quantum Transport in Graphene

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Transport

Background:

• Two-dimensional materials (2DMs) are inherently electro-mechanical systems sensitive to environmental strain.
• Mechanical strain significantly impacts quantum transport properties, including conductance and superconductivity in materials like graphene.
• Understanding these strain effects is crucial for developing novel 2DM-based technologies.

Purpose of the Study:

• To quantitatively measure and model the effects of mechanical strain on quantum transport in graphene transistors.
• To investigate the role of mechanically-induced scalar and vector potentials in modifying graphene's electronic properties.
• To demonstrate precise control over strain and electrostatics in suspended graphene devices.

Main Methods:

• Fabrication of suspended graphene transistors on a custom experimental platform.
• Application of tunable uniaxial strain (up to 2.6%) and electrostatic gating at low temperatures.
• Measurement of quantum transport phenomena, including conductance and quantum interference patterns.

Main Results:

• Quantitative agreement between experimental measurements and models of mechanically-induced gauge potentials.
• In situ modification of graphene's work function by up to 25 meV using a mechanically induced scalar potential.
• Suppression of ballistic conductance by up to 30% and control of quantum interferences via mechanically generated vector potentials.

Conclusions:

• Mechanical strain is a powerful tool to precisely control quantum transport in two-dimensional materials.
• Mechanically-induced gauge potentials provide an accurate framework for understanding strain effects in graphene.
• This work enables new avenues for harnessing strain effects in 2DM quantum transport and future technologies.