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Special CM-AMO Seminar | Electron Correlation and Coupling with Phonon in the Trilayer Graphene/hBN Moire Superlattice

Long Ju (MIT)
Monday, November 28, 2022
4:00-5:00 PM
4448 East Hall Map
Zoom link: with the passcode: CM-AMO

ABC-stacked trilayer graphene/hexagonal boron nitride moiré superlattice (TLG/hBN) has emerged as a playground for correlated electron physics. A spectroscopy study of this system is, however, challenging due to the device configuration. In this talk, I will introduce our recent efforts on FTIR photocurrent spectroscopy measurements of dual-gated TLG/hBN. We observed strong gate-tunable optical transitions that originated from the moire flat band. At half-filling of the valence flat band, a broad absorption peak emerges at ~18 meV, indicating direct optical excitation across an emerging Mott gap. Furthermore, I will talk about a unique moire-enabled interlayer electron-phonon coupling phenomenon in this system. The ZO phonon in hBN hybridizes with electron-hole excitations in trilayer graphene and appear as an asymmetric peak in the photocurrent spectrum. This Fano line-shaped peak evolves continuously as we tune the displacement field. I'll talk about the implications of this phenomenon to engineering the physics of moire quantum matters.

Building: East Hall
Event Type: Workshop / Seminar
Tags: Physics, Science
Source: Happening @ Michigan from Department of Physics, CM-AMO Seminars