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arXiv · 1808.00104

Pressure Induced Compression of Flatbands in Twisted Bilayer Graphene

Bheema Lingam Chittari·Nicolas Leconte·Srivani Javvaji·Jeil Jung
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Abstract

We investigate the bandwidth compression due to out of plane pressure of the moire flatbands near charge neutrality in twisted bilayer graphene for a continuous range of small rotation angles of up to $\sim2.5^{\circ}$. The flatband bandwidth minima angles are found to grow linearly with interlayer coupling ω and decrease with Fermi velocity. Application of moderate pressure values of up to 2.5 GPa achievable through a hydraulic press should allow accessing a flatband for angles as large as $\sim 1.5$^{\circ}$ instead of $\sim 1 \circ$ at zero pressure. This reduction of the moiré pattern length for larger twist angle implies an increase of the effective Coulomb interaction scale per moire cell by about 50% and enhance roughly by a factor of $\sim 2$ the elastic energy that resists the commensuration strains due to the moire pattern. Our results suggest that application of pressure on twisted bilayer graphene nanodevices through a hydraulic press will notably facilitate the device preparation efforts required for exploring the ordered phases near magic angle flatbands.

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Bheema Lingam Chittari, Nicolas Leconte, Srivani Javvaji, Jeil Jung. 2018-07-31. Pressure Induced Compression of Flatbands in Twisted Bilayer Graphene. https://doi.org/10.1088/2516-1075%2Faaead3

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