Revealing Electron-Electron Interactions in Graphene at Room Temperature with a Quantum Twisting Microscope

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• Twistable van der Waals heterostructures exhibit unique quantum phases.
• Tunneling spectroscopy is crucial for probing these quantum states.
• Previous limitations in resolution hindered detailed analysis.

Purpose of the Study:

• To enhance the resolution and energy/momentum range of the quantum twisting microscope (QTM).
• To investigate subtle electronic properties in twisted graphene systems.
• To explore electron-electron interactions in two-dimensional materials.

Main Methods:

• Integration of hexagonal boron nitride as a tunneling dielectric in the QTM.
• Performing energy- and momentum-resolved tunneling spectroscopy.
• Utilizing interferometric interlayer tunneling to amplify band-structure modifications.

Main Results:

• Revealed previously inaccessible dispersion features in tunneling between monolayer graphene sheets.
• Observed a logarithmic correction to the Dirac spectrum due to electron-electron interactions (α ≈ 0.32 ± 0.01).
• Demonstrated the ability to resolve these subtle corrections at room temperature.

Conclusions:

• The enhanced QTM offers unprecedented sensitivity for probing quantum phases.
• Strong electron-electron interactions are present in symmetric graphene states.
• The QTM is a powerful tool for studying spectral functions and excitations in 2D systems.