Powered by Indico
v3.2.3
Abstract:
In recent years, the development of advanced spatial- and angle-resolved photoemission spectroscopy technique (Nano-APRES) brings new opportunities in the study of electronic band structure of low dimensional quantum materials. In this talk, I will introduce the status of the first Nano-ARPES system in China - Beamline 07U at Shanghai Synchrotron radiation facility [1] – as well as our recent study on magic angle twisted bilayer graphene (MATBG) system [2]. Despite intensive experimental and theoretical efforts, the origin of the superconductivity in MATBG remains elusive. Using Nano-ARPES technique, we discover replicas of the flat bands in superconducting MATBG samples, which are absent in non-superconducting MATBG. Compared with simulations, the formation of these replicas is attributed to the presence of strong inter-valley electron-phonon coupling to a K-point phonon mode of graphene. This study provides important information for understanding the origin of superconductivity and the unusual electronic properties of MATBG.
Reference:
[1] H. Gao et al. Synchrotron Radiation News 37, 12-17 (2024)
[2] C. Chen et al. Nature 636, 342–347 (2024)
Biography:
Cheng is currently an Assistant professor in School of Physical Science and Technology (SPST) at ShanghaiTech University. He completed his Bachelor degree from University of Science and Technology of China (2014) and a PhD degree from University of Oxford (2018). He then did postdoc research at ShanghaiTech University, Lawrence Berkeley National Lab and University of Oxford (2019-2024). Cheng’s research interest focuses on exploring the electronic structure of low dimensional and topological quantum materials by using the angle resolved photoemission spectroscopy (ARPES).
Date & Time: 10:00-11:30 March 19 (Wednesday), 2025
Venue: TDLI Meeting Room N601
Tencent Video link: https://meeting.tencent.com/crm/Kwdd5nnk1f