Electrons Surf Phason Waves in Moiré Bilayers.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Twisted transition metal dichalcogenide heterobilayers exhibit unique electronic and optical properties due to moiré potentials.
• Understanding the influence of thermal effects on these moiré systems is crucial for device applications.

Purpose of the Study:

• To investigate the impact of thermal fluctuations on the atomic and electronic structure of twisted MoSe2/WSe2 heterobilayers.
• To elucidate the mechanism of charge carrier motion in response to thermal excitations within the moiré lattice.

Main Methods:

• Combined classical molecular dynamics (MD) simulations and ab initio density functional theory (DFT) calculations.
• Analysis of moiré lattice dynamics and charge carrier localization under thermal stress.

Main Results:

• Thermally excited phason modes induce rigid motion of the moiré lattice.
• Low-energy electrons and holes localize in specific stacking regions and follow the moiré lattice's thermal motion.
• Charge carriers effectively 'surf' on thermally excited phason waves.

Conclusions:

• Thermal fluctuations significantly influence charge carrier behavior in twisted heterobilayers.
• The observed 'carrier surfing' phenomenon persists even with substrates or frozen potentials.
• This finding has potential implications for designing advanced charge and exciton transport devices utilizing moiré materials.