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HL: Fachverband Halbleiterphysik
HL 36: Poster III
HL 36.20: Poster
Wednesday, March 20, 2024, 18:00–20:30, Poster E
Electrical transport properties of twisted bilayer graphene with twist angle disorder — •Bei Zheng, Xiaoyue Zhang, Fan Bai, Lina Bockhorn, and Rolf J. Haug — Institut für Festkörperphysik, Leibniz Universität Hannover, 30167 Hannover, Germany
The twisting of the graphene layer opens up a whole new field of rich physics [1]. Especially, the electronic properties of twisted bilayer graphene depend strongly on the twist angle[2,3]. The twisted graphene structures around the magic angle were the first systems to show strong correlation behaviors, such as the rise of superconductivity and Mott’s insulating phase [4,5].
We fabricated two twisted bilayer graphene samples around the magic angle via the “tear and stack” method. We investigated their transport properties by carrying out field effect measurements at different temperatures T from 300 K down to 1.4 K. The samples showed signatures of twist angle disorder and the resulting quantum interference. We analyzed the temperature- and carrier density-dependent conductance fluctuation Δ Gxx and concluded that, although the disorder of twist angle suppresses the superlattice effect and enhances the quantum interference, the coexistence of phase transition and quantum interference still can be observed since the phase-coherence length Lφ is one order of magnitude larger than the moiré superlattice constant λm for both samples. [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, 045008 (2021) [4] Y. Cao et al., Nat. 556, 43-50 (2018) [5] X. Lu et al., Nat. 574, 653-657 (2019)
Keywords: Twisted bilayer graphene; Twist angle disorder; Conductance fluctuation; phase transition