Collective Charge Excitations between Moiré Minibands in Twisted WSe_{2} Bilayers Probed with Resonant Inelastic...

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spectroscopy

Background:

• Twisted transition metal dichalcogenide bilayers exhibit complex electronic structures due to moiré potentials.
• Understanding moiré band formation is crucial for exploring novel electronic and correlated phenomena.

Purpose of the Study:

• To establish resonant inelastic light scattering (RILS) spectroscopy as a tool for probing moiré band formation.
• To investigate inter-moiré-band excitations (IMBEs) in twisted WSe_{2} bilayers.
• To quantify transition energies relevant for correlation physics.

Main Methods:

• Low-temperature resonant inelastic light scattering (RILS) spectroscopy.
• Utilizing collective inter-moiré-band excitations (IMBEs) as a probe.
• Comparison with ab initio based continuum model calculations.

Main Results:

• RILS spectra show resonances matching predicted inter-moiré-band transition energies.
• Observed transitions between the first and second moiré bands at ~8° twist.
• Identified transitions to higher bands at ~3° twist, indicating flat minibands and high density of states.
• Signatures of IMBEs confirm theoretical predictions of band structure deviations.

Conclusions:

• RILS spectroscopy is a viable method for studying moiré band formation and electronic structure.
• Experimental results align with theoretical models, validating the understanding of moiré potentials.
• The study quantifies key transition energies at the K point, essential for exploring correlation physics in twisted WSe_{2} bilayers.