A new imaging concept in spin polarimetry based on the spin-filter effect

Area of Science:

• Materials Science and Engineering
• Condensed Matter Physics
• Nanotechnology

Background:

• Accurate measurement of electron spin polarization is crucial for spintronics and quantum computing.
• Existing methods for spin detection often lack spatial resolution or multichannel capabilities.
• Developing imaging-type spin detectors is essential for visualizing spin distributions.

Purpose of the Study:

• To propose and demonstrate a novel imaging-type 3D spin detector.
• To enable direct transfer of 2D spin-polarized electron distribution to cathodoluminescence (CL) imaging.
• To achieve multichannel 3D vectorial reconstruction of spin polarization.

Main Methods:

• Fabrication of a hybrid ferromagnetic/semiconductor (FM-SC) heterostructure.
• Utilizing spin-exchange interactions in FM films and spin-selective electron-photon conversion in semiconductors.
• Developing a prototype detector with a spin-polarized electron source, NEA photocathode, and semiconductor target.

Main Results:

• Demonstrated the principle of direct 2D spin-polarized electron distribution imaging via CL.
• Measured spatial and polarization-dependent CL intensity from injected spin-polarized electrons.
• Determined the figure of merit for the spin detector as a function of electron kinetic energy and target temperature.

Conclusions:

• The FM-SC junction provides a compact optical method for measuring free-electron beam spin polarization in image-type mode.
• The proposed detector enables 3D vectorial reconstruction of spin polarization.
• This technology holds potential for applications in momentum microscopy and ARPES systems.