Improvement of image-type very-low-energy-electron-diffraction spin polarimeter

TL;DR

This paper introduces a high-resolution, efficient SARPES instrument utilizing a second-generation VLEED spin polarimeter, enabling detailed exploration of spin-resolved electronic structures in quantum materials.

Contribution

The development and demonstration of a second-generation VLEED spin polarimeter with improved resolution and stability for SARPES measurements.

Findings

Achieved 7.2 meV energy and 0.52° angular resolution.

Confirmed spin polarization in Bi(111) bulk and surface states.

Validated performance with DFT calculations and experimental measurements.

Abstract

Spin- and angle-resolved photoemission spectroscopy (SARPES) with high efficiency and resolution plays a crucial role in exploring the fine spin-resolved band structures of quantum materials. Here we report the performance of SARPES instrument with a second-generation home-made multichannel very-low-energy-electron-diffraction (VLEED) spin polarimeter. Its energy and angular resolutions achieve 7.2 meV and 0.52{\deg}. We present the results of SARPES measurements of Bi(111) film to demonstrate its performance. Combined with the density functional theory (DFT) calculations, the spin polarization of the bulk states was confirmed from the spin-layer locking caused by the local inversion asymmetry. The surface states at binding energy of 0.77 eV are found with 1.0 {\pm} 0.11 spin polarization. The better resolutions and stability compared with the first-generation one provide a good platform to investigate the spin-polarized electronic states in materials.