Deflector mode development for Spin-resolved ARPES

Spin-ARPES offers spin resolution in addition to band structure information, which is not accessible by conventional ARPES, hence providing an orthogonal degree of freedom for exploring nontrivial topology, magnetism, and strong correlations in materials.  Spin-ARPES faces severe experimental challenges compared to conventional ARPES, such as lower efficiency and difficulties achieving comparable angle/energy resolutions. Therefore, it is crucial to push for instrumentation development to improve the overall performance of the spin-ARPES technique.

In this talk, we will demonstrate the functionality of our spin-ARPES setup by presenting spin-resolved spectra on the topological insulator Bi₂Te₃, which not only showcases the warping of its topological surface state but also exhibits a clear out-of-plane spin texture approaching the Fermi level, consistent with the theory prediction. Meanwhile, we will introduce our recent instrumentation development: a deflector mode to map out band structures via electrostatically deflecting photoelectron trajectories. By implementing it, we minimize the need for sample rotation during measurements, preventing the deviation of beam alignment and hence improving the overall sampling efficiency. Spectrum calibration and energy resolution optimization will also be discussed.