Back to Search
Start Over
Gate-Tunable Transport in Quasi-One-Dimensional α-Bi 4 I 4 Field Effect Transistors.
- Source :
-
Nano letters [Nano Lett] 2022 Feb 09; Vol. 22 (3), pp. 1151-1158. Date of Electronic Publication: 2022 Jan 25. - Publication Year :
- 2022
-
Abstract
- Bi <subscript>4</subscript> I <subscript>4</subscript> belongs to a novel family of quasi-one-dimensional (1D) topological insulators (TIs). While its β phase was demonstrated to be a prototypical weak TI, the α phase, long thought to be a trivial insulator, was recently predicted to be a rare higher order TI. Here, we report the first gate tunable transport together with evidence for unconventional band topology in exfoliated α-Bi <subscript>4</subscript> I <subscript>4</subscript> field effect transistors. We observe a Dirac-like longitudinal resistance peak and a sign change in the Hall resistance; their temperature dependences suggest competing transport mechanisms: a hole-doped insulating bulk and one or more gate-tunable ambipolar boundary channels. Our combined transport, photoemission, and theoretical results indicate that the gate-tunable channels likely arise from novel gapped side surface states, two-dimensional (2D) TI in the bottommost layer, and/or helical hinge states of the upper layers. Markedly, a gate-tunable supercurrent is observed in an α-Bi <subscript>4</subscript> I <subscript>4</subscript> Josephson junction, underscoring the potential of these boundary channels to mediate topological superconductivity.
Details
- Language :
- English
- ISSN :
- 1530-6992
- Volume :
- 22
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Nano letters
- Publication Type :
- Academic Journal
- Accession number :
- 35077182
- Full Text :
- https://doi.org/10.1021/acs.nanolett.1c04264