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arXiv · 2507.12991

Enhanced Phonon-Assisted Tunneling in Metal -- Twisted Bilayer Graphene Junctions

Radhika Soni·Suvronil Datta·Robin Bajaj·Saisab Bhowmik·Shinjan Mandal·Baladitya Suri·Kenji Watanabe·Takashi Taniguchi·Manish Jain·U. Chandni
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Abstract

We report planar tunneling spectroscopy measurements on metal-WSe$_2$-twisted bilayer graphene heterostructures across a broad range of gate and bias voltages. The observed experimental features are attributed to phonon-assisted tunneling and the significantly high density of states within the moiré bands. A notable finding is the enhanced phonon-assisted tunneling in twisted bilayer graphene compared to Bernal bilayer graphene, which arises from a more relaxed in-plane momentum matching criterion. Theoretical calculations of phonon dispersions enable us to identify low-energy phonon modes in both Bernal and twisted bilayers of graphene, thereby elucidating the underlying mechanism of tunneling. Our results establish planar tunneling as a versatile tool to further understand electron-phonon coupling in twisted van der Waals materials.

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Radhika Soni, Suvronil Datta, Robin Bajaj, Saisab Bhowmik, Shinjan Mandal, Baladitya Suri, Kenji Watanabe, Takashi Taniguchi, Manish Jain, U. Chandni. 2025-07-17. Enhanced Phonon-Assisted Tunneling in Metal -- Twisted Bilayer Graphene Junctions. https://doi.org/10.1021/acsnano.5c06662

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