Based on the interdisciplinary integration of condensed matter physics, materials science and information science, the laboratory is oriented to major frontier scientific issues such as quantum control and the major needs of national economic development, and focuses on the design, preparation, properties and applications of microstructure materials To design and prepare new structures of micro, sub-micro and nano scales, reveal new quantum effects, and develop quantum control science with quantum control research, artificial nano-structured materials and devices as the main research directions, and other major scientific issues and key technologies. It is reported that the State Key Laboratory of Solid Microstructure Physics of Nanjing University was established in 1984 and is one of the first state key laboratories invested and constructed by the State Planning Commission. At the same time, it is proved that high-order harmonic generation is an effective optical method for studying the energy band structure and topological characteristics of quantum materials with complex electronic energy band structure.
Lay the foundation for the use of topological semi-metallic state as an application to generate deep ultraviolet light. This result proves that Weyl semi-metal can effectively generate high-order harmonics. Combined with the theoretical fitting of the high-order harmonic spectrum dependent on the crystal orientation, the electronic band structure and Bailey curvature characteristics of β-WP2 can also be deduced from the experimental data. Theoretically, this is described quantitatively: odd-order high-order harmonics are derived from the Bloch oscillation of the electron, and even-order high-order harmonics are derived from the peak Berry curvature at the Weir point. The sub-harmonic (up to 10th order) realizes the output of vacuum ultraviolet light (190nm). That is: based on the Bloch oscillation principle with Bailey curvature, the mechanism of the odd and even high-order harmonic generation in the Weyl semimetal is explained.Įxperimentally, the research team prepared high-quality β-WP2 single crystals, using a 1900 nm femtosecond laser, and under the excitation of relatively low laser intensity (~0.29 TW/cm2), both odd and even orders were observed at the same time. This paper finds that the Bailey curvature in the Weyl semimetal is the reason for the effective generation of even-order high-order harmonics. At the same time, first calculation and angle-resolved photoelectron spectroscopy experiments show that there is a peak Berry curvature at the Weyl points of β-WP2. Among them, Weyl semimetal β-WP2 crystal has a mobility of 106 cm2/(Vs). Related research work was published in the journal “Nature Communications” with the title “High-harmonic generation in Weyl semimetal β-WP2 crystals”.Īccording to the official website of Nanjing University, Weyl semimetal is a novel quantum state, and its electron mobility is usually high. It has the advantages of all solid state and easy manipulation. This technology can achieve a solid-state deep-ultraviolet light output, compared with the existing technology that uses liquid tin to generate deep-ultraviolet lasers. Under the laser intensity, Realize the output of deep ultraviolet light (190nm). Using near-infrared femtosecond lasers, it can effectively output high-harmonic generations at the same time. It is reported that the research team found for the first time experimentally that the Weir semi-metal β-WP2 can effectively output both odd and even high-order harmonics (High-harmonic generations) at the same time.
Recently, the research groups of the State Key Laboratory of Solid Microstructure Physics, the School of Physics, the School of Electronic Science and Engineering, the School of Modern Engineering and Applied Sciences, the Collaborative Innovation Center of Microstructure Science and Technology, Nanjing University, Chen Yanbin, Xie Zhenda and Yao Shuhua Significant progress has been made in the research on the optical effects of Weyl semimetal β-WP2 crystals。