Phonon-mediated room-temperature quantum Hall transport in graphene

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• Quantum Hall (QH) effect typically requires low temperatures.
• Graphene's properties allow for QH effect at higher temperatures.
• Electron-phonon scattering is usually suppressed at low temperatures.

Purpose of the Study:

• Investigate QH effect in graphene at room temperature.
• Determine the role of electron-phonon scattering in QH dissipation.
• Explore novel transport regimes in encapsulated graphene.

Main Methods:

• Studied thermally-activated transport in graphene encapsulated in hexagonal boron nitride (hBN).
• Utilized back-gated devices and varied magnetic fields (B) up to room temperature (RT).
• Correlated high-field QH behavior with zero-field transport mobility.

Main Results:

• Demonstrated that electron-phonon scattering predominantly governs dissipation in the QH phase of encapsulated graphene.
• Observed a novel transport regime at filling factor 2 up to RT.
• Found that high-field QH behavior correlates with zero-field mobility.

Conclusions:

• Graphene encapsulated in hBN enables exploration of phonon-limited resistivity in a high-field regime.
• Extends understanding of scattering mechanisms in graphene under QH conditions.
• Highlights the potential of encapsulated graphene for high-temperature quantum phenomena.