###
Magnetic quantum phase transition in Cr-doped Bi _{2}(Se _{x}Te _{1-x}) _{3} driven by the Stark effect

The interplay between magnetism and topology, as exemplified in the magnetic skyrmion systems, has emerged as a rich playground for finding novel quantum phenomena and applications in future information technology. Magnetic topological insulators (TI) have attracted much recent attention, especially after the experimental realization of quantum anomalous Hall effect. Future applications of magnetic TI hinge on the accurate manipulation of magnetism and topology by external perturbations, preferably with a gate electric field. In this work, we investigate the magneto transport properties of Cr doped Bi

_{2}(Se_{x}Te_{1-x})_{3}TI across the topological quantum critical point (QCP). We find that the external gate voltage has negligible effect on the magnetic order for samples far away from the topological QCP. However, for the sample near the QCP, we observe a ferromagnetic (FM) to paramagnetic (PM) phase transition driven by the gate electric field. Theoretical calculations show that a perpendicular electric field causes a shift of electronic energy levels due to the Stark effect, which induces a topological quantum phase transition and consequently a magnetic phase transition. Finally, the in situ electrical control of the topological and magnetic properties of TI shed important new lights on future topological electronic or spintronic devicemore »- Publication Date:

- Grant/Contract Number:
- AC02-76SF00515

- Type:
- Accepted Manuscript

- Journal Name:
- Nature Nanotechnology

- Additional Journal Information:
- Journal Volume: 12; Journal Issue: 10; Journal ID: ISSN 1748-3387

- Publisher:
- Nature Publishing Group

- Research Org:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)

- Sponsoring Org:
- USDOE

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 36 MATERIALS SCIENCE; surfaces, interfaces and thin films; topological insulators

- OSTI Identifier:
- 1418319

```
Zhang, Zuocheng, Feng, Xiao, Wang, Jing, Lian, Biao, Zhang, Jinsong, Chang, Cuizu, Guo, Minghua, Ou, Yunbo, Feng, Yang, Zhang, Shou-Cheng, He, Ke, Ma, Xucun, Xue, Qi-Kun, and Wang, Yayu.
```*Magnetic quantum phase transition in Cr-doped Bi2(SexTe1-x)3 driven by the Stark effect*. United States: N. p.,
Web. doi:10.1038/NNANO.2017.149.

```
Zhang, Zuocheng, Feng, Xiao, Wang, Jing, Lian, Biao, Zhang, Jinsong, Chang, Cuizu, Guo, Minghua, Ou, Yunbo, Feng, Yang, Zhang, Shou-Cheng, He, Ke, Ma, Xucun, Xue, Qi-Kun, & Wang, Yayu.
```*Magnetic quantum phase transition in Cr-doped Bi2(SexTe1-x)3 driven by the Stark effect*. United States. doi:10.1038/NNANO.2017.149.

```
Zhang, Zuocheng, Feng, Xiao, Wang, Jing, Lian, Biao, Zhang, Jinsong, Chang, Cuizu, Guo, Minghua, Ou, Yunbo, Feng, Yang, Zhang, Shou-Cheng, He, Ke, Ma, Xucun, Xue, Qi-Kun, and Wang, Yayu. 2017.
"Magnetic quantum phase transition in Cr-doped Bi2(SexTe1-x)3 driven by the Stark effect". United States.
doi:10.1038/NNANO.2017.149. https://www.osti.gov/servlets/purl/1418319.
```

```
@article{osti_1418319,
```

title = {Magnetic quantum phase transition in Cr-doped Bi2(SexTe1-x)3 driven by the Stark effect},

author = {Zhang, Zuocheng and Feng, Xiao and Wang, Jing and Lian, Biao and Zhang, Jinsong and Chang, Cuizu and Guo, Minghua and Ou, Yunbo and Feng, Yang and Zhang, Shou-Cheng and He, Ke and Ma, Xucun and Xue, Qi-Kun and Wang, Yayu},

abstractNote = {The interplay between magnetism and topology, as exemplified in the magnetic skyrmion systems, has emerged as a rich playground for finding novel quantum phenomena and applications in future information technology. Magnetic topological insulators (TI) have attracted much recent attention, especially after the experimental realization of quantum anomalous Hall effect. Future applications of magnetic TI hinge on the accurate manipulation of magnetism and topology by external perturbations, preferably with a gate electric field. In this work, we investigate the magneto transport properties of Cr doped Bi2(SexTe1-x)3 TI across the topological quantum critical point (QCP). We find that the external gate voltage has negligible effect on the magnetic order for samples far away from the topological QCP. However, for the sample near the QCP, we observe a ferromagnetic (FM) to paramagnetic (PM) phase transition driven by the gate electric field. Theoretical calculations show that a perpendicular electric field causes a shift of electronic energy levels due to the Stark effect, which induces a topological quantum phase transition and consequently a magnetic phase transition. Finally, the in situ electrical control of the topological and magnetic properties of TI shed important new lights on future topological electronic or spintronic device applications.},

doi = {10.1038/NNANO.2017.149},

journal = {Nature Nanotechnology},

number = 10,

volume = 12,

place = {United States},

year = {2017},

month = {8}

}

Works referenced in this record:

Topological insulators in Bi

journal, May 2009

_{2}Se_{3}, Bi_{2}Te_{3}and Sb_{2}Te_{3}with a single Dirac cone on the surfacejournal, May 2009

- Zhang, Haijun; Liu, Chao-Xing; Qi, Xiao-Liang
- Nature Physics, Vol. 5, Issue 6, p. 438-442