Topologically Protected Helical States in Minimally Twisted Bilayer Graphene.

Autor: Huang S; Physics Department, University of Arizona, Tucson, Arizona 85721, USA., Kim K; Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USA., Efimkin DK; Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA., Lovorn T; Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA., Taniguchi T; National Institute for Materials Science, 1-1 Namiki Tsukuba Ibaraki 305-0044, Japan., Watanabe K; National Institute for Materials Science, 1-1 Namiki Tsukuba Ibaraki 305-0044, Japan., MacDonald AH; Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA., Tutuc E; Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USA., LeRoy BJ; Physics Department, University of Arizona, Tucson, Arizona 85721, USA.
Jazyk: angličtina
Zdroj: Physical review letters [Phys Rev Lett] 2018 Jul 20; Vol. 121 (3), pp. 037702.
DOI: 10.1103/PhysRevLett.121.037702
Abstrakt: In minimally twisted bilayer graphene, a moiré pattern consisting of AB and BA stacking regions separated by domain walls forms. These domain walls are predicted to support counterpropogating topologically protected helical (TPH) edge states when the AB and BA regions are gapped. We fabricate designer moiré crystals with wavelengths longer than 50 nm and demonstrate the emergence of TPH states on the domain wall network by scanning tunneling spectroscopy measurements. We observe a double-line profile of the TPH states on the domain walls, only occurring when the AB and BA regions are gapped. Our results demonstrate a practical and flexible method for TPH state network construction.
Databáze: MEDLINE
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