Topological insulators are a novel class of quantum matter with a gapped insulating bulk, yet gapless spin-helical Dirac fermion conducting surface states. Here, we report local and non-local electrical and magneto transport measurements in dual-gated BiSbTeSe

_{2}thin film topological insulator devices, with conduction dominated by the spatially separated top and bottom surfaces, each hosting a single species of Dirac fermions with independent gate control over the carrier type and density. We observe many intriguing quantum transport phenomena in such a fully tunable two-species topological Dirac gas, including a zero-magnetic-field minimum conductivity close to twice the conductance quantum at the double Dirac point, a series of ambipolar two-component half-integer Dirac quantum Hall states and an electron-hole total filling factor zero state (with a zero-Hall plateau), exhibiting dissipationless (chiral) and dissipative (non-chiral) edge conduction, respectively. As a result, such a system paves the way to explore rich physics, ranging from topological magnetoelectric effects to exciton condensation.- Publication Date:

- Type:
- Accepted Manuscript

- Journal Name:
- Nature Communications

- Additional Journal Information:
- Journal Volume: 7; Journal ID: ISSN 2041-1723

- Publisher:
- Nature Publishing Group

- Research Org:
- Sandia National Laboratories (SNL), Albuquerque, NM (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States)

- Sponsoring Org:
- USDOE

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

- OSTI Identifier:
- 1258467

```
Xu, Yang, Miotkowski, Ireneusz, and Chen, Yong P.
```*Quantum transport of two-species Dirac fermions in dual-gated three-dimensional topological insulators*. United States: N. p.,
Web. doi:10.1038/ncomms11434.

```
Xu, Yang, Miotkowski, Ireneusz, & Chen, Yong P.
```*Quantum transport of two-species Dirac fermions in dual-gated three-dimensional topological insulators*. United States. doi:10.1038/ncomms11434.

```
Xu, Yang, Miotkowski, Ireneusz, and Chen, Yong P. 2016.
"Quantum transport of two-species Dirac fermions in dual-gated three-dimensional topological insulators". United States.
doi:10.1038/ncomms11434. https://www.osti.gov/servlets/purl/1258467.
```

```
@article{osti_1258467,
```

title = {Quantum transport of two-species Dirac fermions in dual-gated three-dimensional topological insulators},

author = {Xu, Yang and Miotkowski, Ireneusz and Chen, Yong P.},

abstractNote = {Topological insulators are a novel class of quantum matter with a gapped insulating bulk, yet gapless spin-helical Dirac fermion conducting surface states. Here, we report local and non-local electrical and magneto transport measurements in dual-gated BiSbTeSe2 thin film topological insulator devices, with conduction dominated by the spatially separated top and bottom surfaces, each hosting a single species of Dirac fermions with independent gate control over the carrier type and density. We observe many intriguing quantum transport phenomena in such a fully tunable two-species topological Dirac gas, including a zero-magnetic-field minimum conductivity close to twice the conductance quantum at the double Dirac point, a series of ambipolar two-component half-integer Dirac quantum Hall states and an electron-hole total filling factor zero state (with a zero-Hall plateau), exhibiting dissipationless (chiral) and dissipative (non-chiral) edge conduction, respectively. As a result, such a system paves the way to explore rich physics, ranging from topological magnetoelectric effects to exciton condensation.},

doi = {10.1038/ncomms11434},

journal = {Nature Communications},

number = ,

volume = 7,

place = {United States},

year = {2016},

month = {5}

}