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# Spin tunnel field-effect transistors based on two-dimensional van der Waals heterostructures

## Abstract

A transistor based on spin rather than charge—a spin transistor—could potentially offer non-volatile data storage and improved performance compared with traditional transistors. Many approaches have been explored to realize spin transistors, but their development remains a considerable challenge. The recent discovery of two-dimensional magnetic insulators such as chromium triiodide (CrI3), which offer electrically switchable magnetic order and an effective spin filtering effect, can provide new operating principles for spin transistors. Here, we report spin tunnel field-effect transistors (TFETs) based on dual-gated graphene/CrI3/graphene tunnel junctions. The devices exhibit an ambipolar behaviour and tunnel conductance that is dependent on the magnetic order in the CrI3 tunnel barrier. The gate voltage switches the tunnel barrier between interlayer antiferromagnetic and ferromagnetic states under a constant magnetic bias near the spin-flip transition, thus effectively and reversibly altering the device between a low and a high conductance state, with large hysteresis. By electrically controlling the magnetization configurations instead of the spin current, our spin TFETs achieve a high–low conductance ratio approaching 400%, suggesting they could be of value in the development of non-volatile memory applications.

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## Data availability

The data supporting the plots within this paper and other findings of this study are available from the corresponding authors upon request.

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## Acknowledgements

The research was supported by the National Science Foundation (NSF) under award DMR-1807810 for the sample and device fabrication, the Office of Naval Research (ONR) under award N00014-18-1-2368 for the device characterization, and the Air Force Office of Scientific Research (AFOSR) Hybrid Materials MURI under award FA9550-18-1-0480 for optical measurements. This work was also partially supported by the Cornell Center for Materials Research with funding from the NSF MRSEC programme (DMR-1719875) for low-temperature studies. It was performed in part at Cornell NanoScale Facility, an NNCI member supported by NSF grant NNCI-1542081.

## Author information

S.J., J.S. and K.F.M. designed the study and co-wrote the manuscript. S.J. performed the bulk of the measurements and data analysis. L.L. and Z.W. contributed to the sample and device fabrication. All authors discussed the results and commented on the manuscript.

### Competing interests

The authors declare no competing interests.

Correspondence to Jie Shan or Kin Fai Mak.

## Supplementary information

### Supplementary Information

Supplementary Sections 1–8 and Supplementary Figs. 1–12.

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