Electrostatic Coupling between Two Surfaces of a Topological Insulator Nanodevice
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PhysRevLett.113.206801.pdf
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Author(s)
Fatemi, Valla
Hunt, Benjamin Matthew
Steinberg, Hadar
Eltinge, Stephen L.
Mahmood, Fahad
Butch, Nicholas P.
Watanabe, Kenji
Taniguchi, Takashi
Gedik, Nuh
Jarillo-Herrero, Pablo
Date Issued
November 2014
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Fatemi, Valla, Benjamin Hunt, Hadar Steinberg, Stephen L. Eltinge, Fahad Mahmood, Nicholas P. Butch, Kenji Watanabe, et al. “Electrostatic Coupling Between Two Surfaces of a Topological Insulator Nanodevice.” Physical Review Letters 113, no. 20 (November 2014). © 2014 American Physical Society
Version
Final published version
Abstract
We report on electronic transport measurements of dual-gated nanodevices of the low-carrier density topological insulator (TI) Bi[subscript 1.5]Sb[subscript 0.5]Te[subscript 1.7]Se[subscript 1.3]. In all devices, the upper and lower surface states are independently tunable to the Dirac point by the top and bottom gate electrodes. In thin devices, electric fields are found to penetrate through the bulk, indicating finite capacitive coupling between the surface states. A charging model allows us to use the penetrating electric field as a measurement of the intersurface capacitance C[subscript TI] and the surface state energy-density relationship μ(n), which is found to be consistent with independent angle-resolved photoemission spectroscopy measurements. At high magnetic fields, increased field penetration through the surface states is observed, strongly suggestive of the opening of a surface state band gap due to broken time-reversal symmetry.
MIT Department
Massachusetts Institute of Technology. Department of Physics
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.113.206801
