Interface-induced Superconductivity in Magnetic Topological Insulators
Result of the Month
Interface-induced superconductivity in Cr-doped (Bi, Sb)2Te3/FeTe heterostructures.
Author: Hemian Yi, Yi-Fan Zhao, Ying-Ting Chan, Jiaqi Cai, Ruobing Mei, Xianxin Wu, Zi-Jie Yan1,Ling-Jie Zhou, Ruoxi Zhang, Zihao Wang, Stephen Paolini, Run Xiao, Ke Wang, Anthony R. Richardella, John Singleton, Laurel E. Winter, Thomas Prokscha, Zaher Salman,Andreas Suter, Purnima P. Balakrishnan, Alexander J. Grutter, Moses H. W. Chan, Nitin Samarth, Xiaodong Xu, Weida Wu, Chao-Xing Liu, Cui-Zu Chang
Institute:
''The Pennsylvania State University''
Science URL: https://www.science.org/doi/full/10.1126/science.adk1270 Date: 8/2024
Instruments:
Lab10 MBE System, ARPES Lab
The interface between two different materials can show unexpected quantum phenomena. In this study, we used molecular beam epitaxy to synthesize heterostructures formed by stacking together two magnetic materials, a ferromagnetic topological insulator (TI) and an antiferromagnetic iron chalcogenide (FeTe). We observed emergent interface-induced superconductivity in these heterostructures and demonstrated the co-occurrence of superconductivity, ferromagnetism, and topological band structure in the magnetic TI layer—the three essential ingredients of chiral topological superconductivity (TSC). The unusual coexistence of ferromagnetism and superconductivity is accompanied by a high upper critical magnetic field that exceeds the Pauli paramagnetic limit for conventional superconductors at low temperatures. These magnetic TI/FeTe heterostructures with robust superconductivity and atomically sharp interfaces provide an ideal wafer-scale platform for the exploration of chiral TSC and Majorana physics.
(A) Schematic lattice structure of the Cr-doped (Bi, Sb)2Te3/FeTe heterostructure. (B) Cross-sectional STEM image of the (8,50) heterostructures grown on heat-treated SrTiO3 (100) substrate. (C) In-situ ARPES band map of the (8,50) heterostructure. The Dirac point is located near the chemical potential. The ARPES measurements are performed at room temperature. (D) Temperature dependence of the sheet longitudinal resistance R of the (m, 20) heterostructures with m=1, 2, 4, 8. (E) Temperature dependence of R of the (8, n) FeTe heterostructures with 6≤n≤50.
Coexistence of ferromagnetism and superconductivity in Cr-doped (Bi, Sb)2Te3/FeTe heterostructures.
(A) Temperature dependence of the sheet longitudinal resistance R of the (8,50) heterostructure. (B) Magnetic field u0H dependence of the Hall resistance Ryx at T=10K (black), T=12K (red), and T=14K (blue). (C) u0H dependence of the RMCD signal of the (8,50) heterostructure. For T < Tc,0, the sample shows a hysteresis loop, indicating the coexistence of ferromagnetism and superconductivity.
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