Interfacial superconductivity induced by single-quintuple-layer Bi$_2$Te$_3$ on top of FeTe forming van-der-Waals heterostructure

Hailang Qin; Bin Guo; Linjing Wang; Meng Zhang; Bochao Xu; Kaige Shi; Tianluo Pan; Liang Zhou; Yang Qiu; Bin Xi; Iam Keong Sou; Dapeng Yu; Wei-Qiang Chen; Hongtao He; Fei Ye; Jia-Wei Mei; Gan Wang

arXiv · 1903.06485

Interfacial superconductivity induced by single-quintuple-layer Bi$_2$Te$_3$ on top of FeTe forming van-der-Waals heterostructure

Hailang Qin·Bin Guo·Linjing Wang·Meng Zhang·Bochao Xu·Kaige Shi·Tianluo Pan·Liang Zhou·Yang Qiu·Bin Xi·Iam Keong Sou·Dapeng Yu·Wei-Qiang Chen·Hongtao He·Fei Ye·Jia-Wei Mei·Gan Wang

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Abstract

We report the first clear observation of interfacial superconductivity on top of FeTe(FT) covered by one quintuple-layer Bi$_2$Te$_3$(BT) forming van-der-Waals heterojunction. Both transport and scanning tunneling spectroscopy measurements confirm the occurrence of superconductivity at a transition temperature T$_c$ = 13~K, when a single-quintuple-layer BT is deposited on the non-superconducting FT surface. The superconductivity gap decays exponentially with the thickness of BT, suggesting it occurs at the BT-FT interface and the proximity length is above 5-6~nm. We also measure the work function's dependence on the thickness of BT, implying a charge transfer may occur at the BT/FT interface to introduce hole doping into the FT layer, which may serve as a possible candidate for the superconducting mechanism. Our BT/FT heterojunction provides a clean system to study the unconventional interfacial superconductivity.

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Hailang Qin, Bin Guo, Linjing Wang, Meng Zhang, Bochao Xu, Kaige Shi, Tianluo Pan, Liang Zhou, Yang Qiu, Bin Xi, Iam Keong Sou, Dapeng Yu, Wei-Qiang Chen, Hongtao He, Fei Ye, Jia-Wei Mei, Gan Wang. 2019-03-15. Interfacial superconductivity induced by single-quintuple-layer Bi$_2$Te$_3$ on top of FeTe forming van-der-Waals heterostructure. https://arxiv.org/abs/1903.06485

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