Laser-based angle-resolved photoemission spectroscopy with micrometer spatial resolution and detection of three-dimensional spin vector

TL;DR

This paper introduces a highly precise laser-based micro-SARPES system capable of spatially resolving electronic structures and three-dimensional spin vectors at micrometer scales, demonstrated on topological insulators and patterned substrates.

Contribution

The paper presents a novel micro-SARPES setup combining high spatial, energy, and spin resolution, enabling detailed three-dimensional spin vector measurements at micrometer scales.

Findings

Achieved energy resolution of 1.5 meV without spin detection.

Spatial resolution better than 10 micrometers.

Successfully demonstrated 3D spin vector detection on topological insulators.

Abstract

We have developed a state-of-the-art apparatus for laser-based spin- and angle-resolved photoemission spectroscopy with micrometer spatial resolution (micro-SARPES). This equipment is achieved through the combination of a high-resolution photoelectron spectrometer, a 6-eV laser with high photon flux that is focused down to a few micrometers, a high-precision sample stage control system, and a double very-low-energy-electron-diffraction spin detector. The setup achieves an energy resolution of 1.5 (5.5) meV without (with) the spin detection mode, compatible with a spatial resolution better than 10 micrometers. This enables us to probe both spatially-resolved electronic structures and vector information of spin polarization in three dimensions. The performance of micro-SARPES apparatus is demonstrated by presenting ARPES and SARPES results from topological insulators and Au photolithography patterns on a Si (001) substrate.