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Signatures of hot carriers and hot phonons in the re-entrant metallic and semiconducting states of Moiré-gapped graphene
Author(s)
Nathawat, Jubin
Mansaray, Ishiaka
Sakanashi, Kohei
Wada, Naoto
Randle, Michael D.
Yin, Shenchu
He, Keke
Arabchigavkani, Nargess
Dixit, Ripudaman
Barut, Bilal
Zhao, Miao
Kim, Gil Ho
Watanabe, Kenji
Taniguchi, Takashi
Aoki, Nobuyuki
Han, Jong E.
Bird, Jonathan P.
Date Issued
December 1, 2023
Type
Article
Abstract
Stacking of graphene with hexagonal boron nitride (h-BN) can dramatically modify its bands from their usual linear form, opening a series of narrow minigaps that are separated by wider minibands. While the resulting spectrum offers strong potential for use in functional (opto)electronic devices, a proper understanding of the dynamics of hot carriers in these bands is a prerequisite for such applications. In this work, we therefore apply a strategy of rapid electrical pulsing to drive carriers in graphene/h-BN heterostructures deep into the dissipative limit of strong electron-phonon coupling. By using electrical gating to move the chemical potential through the “Moiré bands”, we demonstrate a cyclical evolution between metallic and semiconducting states. This behavior is captured in a self-consistent model of non-equilibrium transport that considers the competition of electrically driven inter-band tunneling and hot-carrier scattering by strongly non-equilibrium phonons. Overall, our results demonstrate how a treatment of the dynamics of both hot carriers and hot phonons is essential to understanding the properties of functional graphene superlattices.
Citation
Nature Communications, 14(1), 2023