1. Discovery of segmented Fermi surface induced by Cooper pair momentum.
- Author
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Zhu, Zhen, Papaj, Michał, Nie, Xiao-Ang, Xu, Hao-Ke, Gu, Yi-Sheng, Yang, Xu, Guan, Dandan, Wang, Shiyong, Li, Yaoyi, Liu, Canhua, Luo, Jianlin, Xu, Zhu-An, Zheng, Hao, Fu, Liang, and Jia, Jin-Feng
- Subjects
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FERMI surfaces , *COOPER pair , *DOPPLER effect , *QUASIPARTICLES , *BISMUTH telluride , *NIOBIUM compounds - Abstract
A sufficiently large supercurrent can close the energy gap in a superconductor and create gapless quasiparticles through the Doppler shift of quasiparticle energy caused by finite Cooper pair momentum. In this gapless superconducting state, zero-energy quasiparticles reside on a segment of the normal-state Fermi surface, whereas the remaining Fermi surface is still gapped. We use quasiparticle interference to image the field-controlled Fermi surface of bismuth telluride (Bi2Te3) thin films under proximity effect from the superconductor niobium diselenide (NbSe2). A small applied in-plane magnetic field induces a screening supercurrent, which leads to finite-momentum pairing on the topological surface states of Bi2Te3. We identify distinct interference patterns that indicate a gapless superconducting state with a segmented Fermi surface. Our results reveal the strong impact of finite Cooper pair momentum on the quasiparticle spectrum. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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