Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 25: Poster 1

HL 25.10: Poster

Mittwoch, 7. September 2022, 18:00–20:00, P2

Transport Measurements on Twisted Graphene Heterostructures around Magic Angle — •Bei Zheng, Xiao Yue Zhang, Jun Hui Huang, Lina Bockhorn, and Rolf J. Haug — Institut für Festkörperphysik, Leibniz Universität Hannover, 30167 Hannover, Germany

The twisting of graphene layers opens up a whole new field of rich physics [1]. Especially, the electronic properties of twisted (double Bernal-stacked) bilayer graphene layers depend strongly on the twist angle, owing to the energy band modulation from the corresponding Moiré superlattice [2,3]. Furthermore, twisted graphene structures around the magic angle were the first systems that show new many-body phases, as e. g. superconductivity or Mott insulator phases [4].

We fabricated twisted graphene heterostructures around the magic angle encapsulated in hexagonal boron via ’tear and stack’ method and investigated their transport characteristics at low temperature down to 1.5 K. The longitudinal resistance was observed to periodically change with charge carrier concentration. The periodicity is relative to the superlattice density n_s and depends on how the degenerated superlattice sub-bands are filled.

[1] H. Schmidt et al., Nat. Commun. 5, 5742 (2014)

[2] J. C. Rode et al., 2D Mater. 3, 035005 (2016)

[3] S. J. Hong et al., 2D Mater. 8, 045009 (2021)

[4] Y. Cao et al., Nat. 556, 43-50 (2018)