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arXiv · 2001.09916

Tunable bandwidths and gaps in twisted double bilayer graphene system on the verge of correlations

Pratap Chandra Adak·Subhajit Sinha·Unmesh Ghorai·L. D. Varma Sangani·Kenji Watanabe·Takashi Taniguchi·Rajdeep Sensarma·Mandar M. Deshmukh
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Abstract

We use temperature-dependent resistivity in small-angle twisted double bilayer graphene to measure bandwidths and gaps of the bands. This electron-hole asymmetric system has one set of non-dispersing bands that splits into two flat bands with the electric field - distinct from the twisted bilayer system. With electric field, the gap between two emergent flat bands increases monotonically and bandwidth is tuned from 1 meV to 15 meV. These two flat bands with gap result in a series of thermally induced insulator to metal transitions - we use a model, at charge neutrality, to measure the bandwidth using only transport measurements. Having two flat bands with tunable gap and bandwidth offers an opportunity to probe the emergence of correlations.

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Pratap Chandra Adak, Subhajit Sinha, Unmesh Ghorai, L. D. Varma Sangani, Kenji Watanabe, Takashi Taniguchi, Rajdeep Sensarma, Mandar M. Deshmukh. 2020-01-27. Tunable bandwidths and gaps in twisted double bilayer graphene system on the verge of correlations. https://doi.org/10.1103/physrevb.101.125428

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