Vacuum Homogeneous Emulsifier,Vacuum Emulsifying Mixer,Vacuum Homogenizing Emulsifier,Excellent Vacuum Emulsifier Wuxi Mingyan Equipment Co., Ltd , https://www.wxmygroup.com
Research progress on pressure-induced phonon bottleneck effect
[ Instrument R & D of Instrument Network ] Ultrafast spectroscopy and high-pressure physics are one of the frontier fields of condensed matter physics. The ultrafast spectroscopic method is characterized by its extremely high time resolution, the detection of electronic excited states above the Fermi surface, the interaction of a full-wavelength wide-spectrum energy range, the generation and detection of coherent and collective excited states, and the detection of symmetrical breaks in the surface interface These advantages have important applications in the research of condensed matter physics, especially related quantum materials. People have used this method to obtain high-temperature superconducting mechanisms, complex phase transitions, multi-degree-of-freedom coupling, laser coherent modulation, and induction of novel quantum states. Many important research achievements have been made; however, ultrafast spectroscopy has so far mainly been used to study the physical properties of condensed matter under normal pressure.
On the other hand, pressure is a relatively "clean" experimental method. It does not introduce stoichiometric ratio, additional charge carriers, and lattice disorder. It can directly change the lattice spacing and thus adjust the electronic state of the material. New laws, new phenomena, new physics, and regulation of physical properties have been found to be important; however, there has been relatively little research on the ultrafast kinetics of excited states and the non-equilibrium high-pressure physical properties above the Fermi surface in the field of high pressure, especially to ensure the true In-situ high-pressure ultrafast spectroscopy experiments are still little known. How to combine the two will not only achieve breakthroughs and advancements in instrument research and development, but also discover the pressure-induced ultra-fast kinetic properties, which is an interesting scientific problem that is expected to open up a new cross-cutting field. Since the pump-probe experiment has two beams that need to be spatially overlapped, the associated quantum materials often also have in-plane fluctuations, which needs to ensure that the diamond does not move in place on the top anvil during pressure and calibration. Most of the previous in-situ high-pressure experiments refer to the sample not taking out the counter anvil, and the entire counter anvil is taken out of the optical path to pressurize and compress, which is particularly likely to be brought about in the double beam experiment such as pump-probe Human error.
Recently, Zhao Jimin, a researcher at the State Key Laboratory of Surface Physics of the Institute of Physics, Chinese Academy of Sciences / Beijing National Research Center for Condensed Matter Physics, and his postdoctoral student Wu Yanling, master student Gazira Hasain, and Ding Yang, a researcher at the Beijing High Voltage Scientific Research Center, and his master Sheng Yinxia cooperated and made new progress in high-pressure ultrafast spectroscopy. They successfully built a set of "on-site in situ" high-pressure pump–probe ultrafast spectroscopy experimental equipment and used this set The device studied the high-pressure ultrafast dynamics of the strongly correlated quantum material Sr2IrO4. For the first time, the pressure-induced phonon bottleneck effect was observed, corresponding to a sharp decrease in the energy gap in the electronic structure. All the previously known phonon bottleneck effects are caused by temperature regulation, and the phonon bottleneck effect regulated by high pressure induction is still new physical knowledge. During the entire experiment, the high-pressure sample cavity was not moved out of the optical path, avoiding the movement and rotation of the sample, and clearly enhancing the accuracy and reliability of the ultra-fast data of voltage transformation. The maximum achievable pressure adjustment range of this device is 45 GPa, which is expected to be extended to 70 GPa or higher; the time resolution is consistent with the traditional pump-probe experiment. This research organically combines high-pressure physics with ultrafast spectroscopy. The research results will drive the opening, shaping and development of a new branch of "high-pressure ultrafast kinetics", which is important for promoting condensed matter physics research under extreme conditions. significance.
The research was supported by the Chinese Academy of Sciences Innovation Innovation Team, Key Foreign Cooperation Projects (GJHZ1826, GJHZ1403), Pilot Project (XDB30000000), Fund Committee (11774408, 11574383, 11874075, U1530402), Challenge Program (TZ2016001), and Key Projects of Beijing Natural Science Foundation ( 4191003) and other support.