On the morning of April 1^st 2017, Prof. Xie Xincheng, member of the Chinese Academy of Sciences, Dean of the Peking University Physics Institute and condensed matter physicist, was invited to give a lecture entitled “Quantum Materials: Superconductivity and Topology Insulators”. Yu Dapeng, Director of the Physics department of SUSTech presided over the event which was held in the lecture hall 110 of the library.

Lecture hall 110

Pr. Xie started the talk on the topic of superconductors,using graphics to introduce the particle classification and the basic characteristics, from the phenomenological theory to the tunneling effect. He also shared many scientific anecdotes and vivid examples to the audience to illustrate the wonders of the world of physics. In explaining the microscopic theory of superconductivity and conventional superconductors (BCS theory), he compares abstract physical concepts to imagination-friendly examples to help the audience quickly understand how the probability of an electronic collision is diminished or even eliminated. He also referred to the Josephson effect to symbolize the experience of electronic tunneling, warning the students: on the path of scientific research, one should not be superstitious and blindly follow the authority. Think independently, and follow your own ideas. Pr. Xie went on to show the concept of a topological insulator using an animation, further explaining the Hall effect and the link to the quantum Hall effect.

The lecture was concluded with a question and answer session, during which Pr. Xie said that scientists have studied superconductors for a long time, so the applications are already quite broad. However the field is facing difficulties in pushing past the current limits, and that topology – which has a much shorter history of research – may offer some interesting new areas of study. At the moment the applications between the two might seem far apart but we shouldn’t rule out that in the future the two could be integrated to develop new applications and areas of study.

Biography

Professor Xie is on of the leading experts in China on condensed matter physics, and is a member of the Thousands Talent Program, as well as Dean of the Physics Department at Pekin University. In 2015 he was elected to become a member of the Chinese Academy of Sciences. He has been researching the field of condensed matter physics for a long time and has devoted himself to deepening the theoretical and experimental research in the fields of the quantum Hall effect, spintronics and low-dimensional quantum systems just to name a few, making significant contributions to these areas.

He also studied low-dimensional transmission, for which he used a photon-assisted model to explain the phenomenon of “zero resistance” induced by microwave in the two-dimensional electronic system. The electronic droplet state is used to explain the two-dimensional metal to insulator transition phenomenon. It is predicted that there may be a filling factor of 1/2 in the two-layer system, which is confirmed by the relevant experiments. In the field of spintronics, the definition of spin flow is discussed in detail, and a new scheme and a new model for spin polarization generation and spin transfer control in low-dimensional system are proposed. It is proposed that “spin superconductivity” impacts the new quantum state.