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Coulomb drag in topological wires separated by an air gap


Strong electron–electron interactions between adjacent nanoscale wires can lead to one-dimensional Coulomb drag, where current in one wire induces a voltage in the second wire via Coulomb interactions. This effect creates challenges for the development of nanoelectronic devices. Quantum spin Hall (QSH) insulators are a promising platform for the development of low-power electronic devices due to their topological protection of edge states from non-magnetic disorder. However, although Coulomb drag in QSH edges has been considered theoretically, experimental explorations of the effect remain limited. Here, we show that one-dimensional Coulomb drag can be observed between adjacent QSH edges that are separated by an air gap. The pair of one-dimensional helical edge states is created in split H-bar devices in inverted InAs/GaSb quantum wells. Near the Dirac point, negative drag signals dominate at low temperatures and exhibit a non-monotonic temperature dependence, suggesting that distinct drag mechanisms compete and cancel out at higher temperatures. The results suggest that QSH effects could be used to suppress the impact of Coulomb interactions on the performance of future nanocircuits.

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Fig. 1: Overview of the Coulomb drag set-up.
Fig. 2: Schematics of the topological circuit fabrication processes.
Fig. 3: Drag resistance of helical edge states versus front-gate voltage in the split H-bar device at different temperatures.
Fig. 4: Temperature dependence of Coulomb drag signals in helical edges.

Data availability

The data supporting the findings of this study are available within the paper and its Supplementary Information files or from the corresponding author upon reasonable request.


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We thank M. S. Foster for discussions. The work at Peking University was supported by the NSFC (grant no.11921005), the National Key R and D Program of China (grant no. 2019YFA030840) and the Strategic Priority Research Program of the Chinese Academy of Sciences (grant no. XDB28000000). The work at Nanjing University was supported by the Fundamental Research Funds for the Central Universities (grant no. 14380146) and the NSFC (grant no. 12074177). The work at Rice University was supported by the NSF (grant no. DMR-1508644) and Welch Foundation (grant no. C-1682). Y.-Z.C. is supported by the Laboratory for Physical Sciences and by JQI-NSF-PFC (supported by NSF grant PHY-1607611).

Author information




L.D., J. Zheng, J. Zhang and X.W. fabricated the devices and performed the transport experiments. Y.-Z.C. developed the theoretical model. G.S. and A.I. fabricated the QW samples. L.D. and R.-R.D. co-wrote the manuscript with input from the other authors. L.D. and R.-R.D. conceived the project. R.-R.D. provided overall supervision and coordination of the project.

Corresponding authors

Correspondence to Lingjie Du or Rui-Rui Du.

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The authors declare no competing interests.

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Peer review information Nature Electronics thanks the anonymous reviewers for their contribution to the peer review of this work.

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Supplementary Information

Supplementary Information

Supplementary Figs. 1–7.

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Du, L., Zheng, J., Chou, YZ. et al. Coulomb drag in topological wires separated by an air gap. Nat Electron 4, 573–578 (2021).

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