Role of substrate induced electron-phonon interactions in biased graphitic bilayers

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanoscience

Background:

• Graphitic bilayers show promise for field effect transistors (FETs).
• Applying a potential difference can tune the electronic bandgap of insulating graphitic bilayers, potentially creating semiconductors.
• Graphene bilayers exhibit a small semiconducting gap under an applied field.

Purpose of the Study:

• To investigate the influence of substrate-induced electron-phonon interactions (EPIs) on the field-induced bandgap changes in graphitic bilayers.
• To understand how EPIs affect the bandgap modulation in various lattice configurations of graphitic bilayers.

Main Methods:

• A perturbative approach was used to examine EPIs in different lattice configurations of graphitic bilayers.
• The study analyzed the impact of bias strength and lattice structure on the bandgap.

Main Results:

• Electron-phonon interactions (EPIs) typically lead to an undesirable widening of the bandgap in graphitic bilayers.
• The extent of bandgap widening due to EPIs varies significantly with the lattice structure and applied bias magnitude.
• EPIs have the least impact on the bandgap when the applied bias exceeds the non-interacting gap size, particularly in [Formula: see text] and AB stacked configurations.

Conclusions:

• Minimizing EPIs through careful selection of substrates, lattice configurations, and bias strength is crucial for optimizing the electronic properties of devices based on graphitic bilayers.
• The findings are relevant for Boron Nitride (BN) bilayers and are expected to be qualitatively similar for other graphitic bilayers and metal dichalcogenide bilayers like MoS2 used in FETs.