1Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China 2School of Physical Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China 3Key Laboratory for Quantum Materials of Zhejiang Province, School of Science, Westlake University, Hangzhou 310024, China 4Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, China 5CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China 6CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nano-technology, National Center for Nanoscience and Technology, Beijing 100190, China
Abstract：In marginally twisted bilayer graphene, the Moiré pattern consists of the maximized AB (BA) stacking regions, minimized AA stacking regions and triangular networks of domain walls. Here we realize the strain-modulated electronic structures of marginally twisted bilayer graphene by scanning tunneling microscopy/spectroscopy and density functional theory (DFT) calculations. The experimental data show four peaks near the Fermi energy at the AA regions. DFT calculations indicate that the two new peaks closer to the Fermi level may originate from the intrinsic heterostrain and the electric field implemented by back gate is likely to account for the observed shift of the four peaks. Furthermore, the $dI/dV$ map across Moiré patterns with different strain strengths exhibits a distinct appearance of the helical edge states.
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2022, Vol. 39 
