本学期学术活动

贾金锋:Topological superconductors by proximity effect

2023-04-26    点击:
报告题目:
理学院科学之美讲坛:Topological superconductors by proximity effect
 报告人:
贾金锋

School of Physics and Astronomy, Shanghai Jiao Tong University
Department of Physics, Southern University of Science and Technology
报告时间:
2023-04-28 16:00
报告地点:
理科楼郑裕彤讲堂
主办单位:
理学院(主办),物理系(承办)
  简介:

Topological superconductors attract lots of attentions recently, since they are predicted to host Majorana zero mode (MZM), who behaves like Majorana fermion and can be used in fault-tolerant quantum computation relying on their non-Abelian braiding statistics. Currently, most topological superconductors are artificially engineered based on a normal superconductor and the exotic properties of the electronic surface states of a topological insulator. Here, I will show you that the Bi2Te3/NbSe2 hetero-structure is an ideal artificial topological superconductor. By using spin-polarized scanning tunneling microscopy/spectroscopy (STM/STS), we observed the spin dependent tunneling effect, which is a direct evidence for the spin selective Andreev reflection from MZMs, and fully supported by theoretical analyses. Recently, the segmented Fermi surface induced by the Cooper pair momentum was observed in a Bi2Te3/NbSe2 system. It’s found that the shape and size of this Fermi surface can be adjusted by the direction and magnitude of the magnetic field, and can also modulate the topology to build new topological superconductors. This work opens up a new method to manipulate the property of crystals. Finally, the strong proximity effect was found in SnTe-Pb heterostructure. The bulk pairing gap and multiple in-gap states induced by topological surface states can be clearly distinguished. The superconductivity of SnTe is consistent with a new type of topological superconductors under the protection of lattice symmetries. Under lattice-symmetry protection, the superconducting SnTe is predicted to possess multiple MZMs in a single vortex. This system provides a platform to study the coupling of multiple MZMs without the need of real space movement of a vortex.

Bio:Prof. Jinfeng Jia is currently the vice president of Southern University of Science and Technology. He graduated from Peking University with B.Sc. in 1987 and Ph.D. in 1992. From 2006 to 2009, he worked as a professor at Department of Physics, Tsinghua University. He authored more than 310 SCI papers, including 5 in Science, 3 in Nature Materials, 30 in Physical Review Letters, with a total citation of more than 17000 times. His main research interests include topological superconductors and new quantum materials. He received numerous recognitions, including National Prize for Advancement in Natural Science (Second class, 2004, 2011, 2019), Group Award for Outstanding Science and Technology Achievement from Qiu Shi Science & Technologies Foundation?of Hong Kong, 2011.