Development of a laser-based angle-resolved-photoemission spectrometer with sub-micrometer spatial resolution and...

Area of Science:

• Condensed Matter Physics
• Quantum Materials Science
• Spectroscopy Techniques

Background:

• Angle-resolved photoemission spectroscopy (ARPES) is crucial for quantum material research.
• Achieving sub-micrometer spatial resolution typically requires synchrotron radiation and complex optics.
• Previous methods faced limitations in cost, convenience, and photon flux.

Purpose of the Study:

• To develop a cost-effective, lab-based laser system for high-resolution ARPES.
• To achieve sub-micrometer spatial resolution with spin detection capabilities.
• To enable detailed investigation of local electronic structures in quantum materials.

Main Methods:

• Developed a laser-based μ-ARPES with spin-resolution (LMS-ARPES) using a 177 nm laser.
• Focused the laser beam with an optical lens to achieve sub-micron spatial resolution.
• Utilized a 2D spin detector based on exchange scattering for spin analysis.
• Investigated the topological insulator Bi2Se3.

Main Results:

• Confirmed sub-micron spatial resolution of the laser-based system.
• Achieved higher photon flux (>5 × 10^13 photons/s) compared to synchrotron sources.
• Revealed high spin-polarization and confirmed spin-momentum locking in Bi2Se3.
• Demonstrated the system's capability for high-resolution, high-statistics measurements.

Conclusions:

• The developed lab-based LMS-ARPES system is economical, convenient, and provides high performance.
• This system enables advanced studies of local electronic structures in diverse materials.
• It is a powerful tool for exploring topological quantum materials and other condensed matter systems.