High-Mobility Ambipolar Magnetotransport in Topological Insulator Bi2Se3 Nanoribbons
Journal article, 2021

Nanoribbons of topological insulators (TIs) have been suggested for a variety of applications exploiting the properties of the topologically protected surface Dirac states. In these proposals it is crucial to achieve a high tunability of the Fermi energy, through the Dirac point while preserving a high mobility of the involved carriers. Tunable transport in TI nanoribbons has been achieved by chemical doping of the materials so to reduce the bulk carriers' concentration, however at the expense of the mobility of the surface Dirac electrons, which is substantially reduced. Here we study bare Bi2Se3 nanoribbons transferred on a variety of oxide substrates and demonstrate that the use of a large relative permittivity SrTiO3 substrate enables the Fermi energy to be tuned through the Dirac point and an ambipolar field effect to be obtained. Through magnetotransport and Hall conductance measurements, performed on single Bi2Se3 nanoribbons, we demonstrate that electron and hole carriers are exclusively high-mobility Dirac electrons, without any bulk contribution. The use of SrTiO3 allows therefore an easy field effect gating in TI nanostructures providing an ideal platform to take advantage of the properties of topological surface states.


Gunta Kunakova

University of Latvia

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Thilo Bauch

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Xavier Palermo

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Matteo Salvato

University of Rome Tor Vergata

Jana Andzane

University of Latvia

Donats Erts

University of Latvia

Floriana Lombardi

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Physical Review Applied

2331-7019 (eISSN)

Vol. 16 2 024038

High Frequency Topological Insulator devices for Metrology (HiTIMe)

European Commission (EC) (EC/H2020/766714), 2018-02-01 -- 2022-01-31.

Subject Categories

Atom and Molecular Physics and Optics

Materials Chemistry

Condensed Matter Physics



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