Science Institute of Physics, Chinese Academy of SciencesWuhan University first observation of Reedeburg Moll excitons!
Researchers Yuan Shengjun and Wu Fengcheng of the Wuhan Institute of Quantum Technology, in collaboration with the Institute of Physics of the Chinese Academy of Sciences, Wuhan University, Nankai University, Lanzhou University, and the National Institute of Materials Science of Japan, have discovered Riedbergmohr excitons, and the related results were published in Science on June 29.
The paper is titled "Observation of Rydberg moiré excitons". Qianying Hu and Zhen Zhan are co-first authors, and Yang Xu and Shengjun Yuan are co-corresponding authors. Collaborators also include Researchers Qingming Zhang and Wuming Liu from the Institute of Physics, Chinese Academy of Sciences, Professor Xuewei Cao from Nankai University, and Professor Fengcheng Wu from Wuhan University. The research was supported by the Ministry of Science and Technology, the National Natural Science Foundation of China, the Chinese Academy of Sciences, the Supercomputing Center of Wuhan University, and the Huairou Integrated Extreme Experimental Device.
Riedberg states are excited states of atoms and molecules whose "expanded size" provides enhanced interactions that can be used in quantum simulators and sensor applications.
These states are similar in nature to the highly excited states in the hydrogen atom model, with spatial ductility and large electric dipole moments, and can produce strong responses even under very weak external fields. In recent years, advances in experimental techniques in the field of cold atoms have led to the successful imprisonment and modulation of Riedberg atoms, and quantum simulations and quantum many-body physics studies based on the Riedberg atomic system have received much attention as a result.
Similarly, Riedberg excitons are electron-hole pairs in excited states that have similar properties to Riedberg atoms and are more compatible with modern semiconductor technology.
In the past few years, Distinguished Researcher Yang Xu of the N08 group at the Institute of Physics, Chinese Academy of Sciences (IPC)/National Center for Condensed Matter Physics (NCMP), Beijing, and co-workers have developed a method for optical "Riedberg exciton detection", which exploits the Riedberg exciton state of the two-dimensional semiconductor WSe2 that is sensitive to the dielectric shielding The method exploits the dielectric shielding effect-sensitive nature of the Riedberg exciton state of the two-dimensional semiconductor WSe2 to achieve effective detection of novel electronic states in the near two-dimensional regime. Using this approach, they observed the widespread charge-ordered states in WSe2/WS2 at fractional filling of the Mohr superlattice, also known as generalized Wegener crystal states [Nature 587, 214 (2020)]; and observed the modulation of the WSe2 band gap and exciton response by the formation of a periodic dielectric environment in the graphene/hexagonal boron nitride Mohr superlattice [Nature Materials 20, 645 (2021)]; the simulation and modulation of the two-energy band Hubbard model in bilayer corner WSe2 was studied [Nature Nanotechnology 17, 934 (2022)], etc. However, in these systems, the interlayer interaction between the Riedelberg exciton state and the surrounding dielectric layer is weak, and how to regulate the Riedelberg exciton, form a strong coupling state and achieve spatial confinement becomes the focus of the next research.
To further realize the strongly coupled states of Riedberg excitons, the researchers proposed a method to modulate them using the Mohr potential field generated by the two-dimensional corner superlattice system to achieve spatial confinement.
The Reedeburg induction of Se2 adjacent to 10° and 1.14° TBG.
The theoretical team of Yuan Shengjun and Wu Fengcheng, researchers at the Wuhan Institute of Quantum Research and professors at Wuhan University, used the self-developed large scale computational physics method TBPM and the computational software TBPLaS (www.tbplas.net) to perform electronic structure calculations for a very large system containing up to nearly 10 million atoms, and found that the space charge distribution in the Mohr superlattice plays a The key role is found to be played by the space charge distribution in the Mohr superlattice for this experimental phenomenon.
Combining the methods of the Institute of Physics team and the Wuhan University research team, it was found that the space charge distribution in the Mohr superlattice, which is regulated with the gate pressure, may play a key role in the generation of this experimental phenomenon. In this system, the periodic Mohr potential field generated in corner graphene resembles the optical lattice in the cold atomic system, providing a highly tunable bound potential field for the Riedberg exciton, bringing about a severely asymmetric electron-hole interlayer Coulomb interaction.
In this system, the periodic Mohr potential field generated in the corner graphene is similar to the optical lattice in the cold atomic system, providing a highly tunable bound potential field for the Riedberg exciton.
Riedberg moiré excitons in WSe2 and their gate pressure evolution law.
The present study shows that optically excited Riedberg excitons (excited Coulomb-bound electron-hole pairs) in monolayer tungsten diselenide can be confined and controlled using the narrow and sharp potential wells of the moiré generated in adjacent small-angle twisted bilayer graphene.
This study systematically demonstrates the controlled regulation and spatial confinement for Riedberg moiré excitons, providing novel opportunities for quantum information processing and quantum simulations based on Riedberg states in the solid-state regime, and offering new ways to realize novel quantum technologies and quantum computing.
Reference links:
[1] https://mp.weixin.qq.com/s?__biz=Mzg3Njg3MTkxOA==&mid=2247484550&idx=1&sn=a6cbdaea46c469d64962d7cb734e36fd&chksm= cf2aed07f85d64115d4fd1585d8bbaf6a853b85ace0e4153bc85141ad84d90b48db5dc9bd0de&scene=0&subscene=7#rd
[2]https://mp.weixin.qq.com/s/ELI4RuvISg9LZ7FsbM7wBg
[3]https://www.science.org/doi/10.1126/science.adh1506
[4]http://www.iop.cas.cn/xwzx/kydt/202306/t20230629_6792461.html
