Subject：Rydberg excitons in cuprous oxide

Speaker：Prof. Manfred Bayer

Emcee：Prof. Donghai Feng

Time：2020年10月29日16:00

Place：Tencent Meeting ID：975 896 284

About the Speaker：

   Prof. Manfred Bayer got Diploma in Physics in 1992 and PhD in Physics in 1997 from Universität Würzburg. During 1997-2002, he was a postdoctoral researcher in Universität Würzburg. Since 2002, he is a full professor (C4/W3) in Department of Physics in Technische Universität Dortmund. He is the chairman of Senate in TU Dortmund since 2008, and now the president of TU Dortmund since September 2020. His research field is mainly the laser spectroscopy of condensed matter. He has published more than 500 articles in refereed journals including Nature, Science, Nature Physics / Photonics / Nanotechnology / Materials and so on. He was elected as a fellow of the American Physical Society in 2012 and a foreign member of the Russian Academy of Science in 2016.

Abstract：

Not too much progress had been achieved in studying the exciton hydrogen series, until the combination of high resolution laser spectroscopy and high quality crystal material allowed the extension of the hydrogen series up to n=25 in 2014 [1]. The huge size of these highly excited states makes them the solid-state analogue of the famous Rydberg atoms. The development of our present understanding comprising about 60 optically active, bright exciton shells will be described in detail. Further, very recently, for the first time, the Rydberg series of optically inactive, dark excitons has been demonstrated [2]. Unprecedented insight into exciton physics could be taken by high-resolution spectroscopy using this hardware platform. Some examples will be given such as the behavior of excitons subject to a magnetic field where an area of quantum chaos that could hardly be addressed before could be entered, providing surprising insights. For example, we showed that for excitons in magnetic field all anti-unitary symmetries are broken [3]. The huge exciton size leads to giant interaction effects, for example among each other or with an optically injected electron-hole plasma [4].

References:

[1] T. Kazimierczuk, D. Fröhlich, S. Scheel, H. Stolz, M. Bayer, Nature 514, 343 (2014).

[2] A. Farenbruch, D. Fröhlich, D.R. Yakovlev, and M. Bayer, Phys. Rev. Lett., in press (2020).

[3] M. Aßmann, J. Thewes, D. Fröhlich, and M. Bayer, Nature Materials 15, 741 (2016).

[4] J. Heckötter, M. Freitag, D. Fröhlich, M. Aßmann, M. Bayer, P. Grünwald, F. Schöne, D. Semkat, H. Stolz, and S. Scheel, Phys. Rev. Lett. 121, 097401 (2018).