Recently, the Nano Angle-Resolved Photoemission Spectroscopy (NanoARPES) experimental station at Shanghai Synchrotron Radiation Facility (SSRF), designed and built by ShanghaiTech University, has successfully passed the process of testing and acceptance organized by the Chinese Academy of Sciences. It took six years starting from a preliminary design to finally pass the acceptance. With this success, a new critical research facility has become one of the members of Zhangjiang Large-Scale Scientific Facilities, to serve a wide range of researchers. This is the first NanoARPES in China and the overall performance of the experimental station has achieved the top level in the world.
NanoAPRES experimental station
In ARPES, an X-ray photon from the synchrotron radiation is focused onto a solid sample, generating photoelectrons in a distribution of energies and angles. It is important that the photons are monochromatic, so that the energy and angle of the electrons can be converted into the energy and momentum of the electrons in the solid sample. NanoARPES technology obtains an angular-resolved photoelectron spectrum with spatial resolution capabilities by focusing the synchrotron radiation spot size to the order of hundreds of nanometers (1/100 of the traditional ARPES spot), which greatly expands the research system and scope of ARPES. NanoARPES can efficiently detect the electronic structure of extremely small samples or phase-separated polycrystalline domain materials, and it can also pioneer the study of the electronic properties of local spaces such as sample edges and domain boundaries. It will also have unique advantages in the exploration in frontier scientific issues, such as the electronic structure of low-dimensional material artificial heterogeneity junctions (such as Moire system) and the edge state of topological quantum materials. At present, NanoARPES experimental stations are only deployed to operate on synchrotron radiation beamlines in some developed countries, for example, ALS BL7 in United States, DIAMOND I05 in United Kingdom, SOLEIL ANTARE in France, and ELETTRA Spectromicroscopy in Italy.
This NanoAPRES experimental station was coordinated by ShanghaiTech for its overall construction. During the construction, the project team independently innovated and worked together to overcome multiple technical difficulties such as rotating vacuum chamber design, optical path positioning and diagnosis, precise manipulation for sample position, system stability and low temperature performance, and successfully completed the construction on time.
Group photo of the ShanghaiTech’s project team
A process test expert group formed by five experts from the University of Science and Technology of China, Shanghai Jiaotong University, Institute of High Energy Physics, Chinese Academy of Sciences and Fudan University, were invited to undertake the project review. They reviewed the test content, test methods and test outline in detail, and listened to the project development report and self-test report and conducted a field test. The field test results showed that all the indicators of the NanoARPES experimental station including measured spot, energy resolution, luminous flux and others, met or exceeded the design indicators.
Process acceptance field
Field test results of 200nm spatial resolution of NanoARPES experimental station
The successful completion and process acceptance of the NanoARPES experimental station means that China has broken the international monopoly on this advanced measurement method of photonic science, providing a first-class research platform for domestic scientists. At present, the experimental station has begun to optimize the system and carry out preliminary scientific experimental tests, and will be opened to scientific research users all over the world in the near future.
A quick video on the experimental station assembly process