Detecting the full photoemission cone from laser-based ARPES experiments by leveraging deflector technology

TL;DR

This paper introduces a novel ARPES technique leveraging deflector technology to capture the full photoemission cone, enabling comprehensive electronic structure analysis across various materials and improving time-resolved measurements.

Contribution

It extends previous work by using deflector technology in hemispherical analyzers to detect all emitted electrons in a fixed setup, covering the entire 2π solid angle.

Findings

Successfully detected full photoemission cone in various materials

Enabled consistent measurements for time-resolved ARPES

Demonstrated advantages over traditional analyzers

Abstract

Angle-resolved photoemission spectroscopy (ARPES) provides a direct access to the electronic band structure of solid and molecular systems. The momentum range accessible by this technique depends directly on the photon energy used, and low-photon-energy sources are insufficient to photoemit electrons over the full Brillouin zone of most quantum materials. In addition, while electrons are emitted over a 2$\pi$ solid angle, conventional hemispherical analyzers only collect a small subset of those electrons. A previous work [RSI 92, 123907 (2021)] demonstrated that electrons emitted over a larger field-of-view can be acquired in one fixed configuration by accelerating them towards the analyzer with a bias voltage. Here, we extend this work by leveraging the deflector technology of novel ARPES hemispherical analyzers. We demonstrate the ability to detect all $2\pi$ photoemitted electrons in a fixed configuration for various materials such as gold, cuprates and transition-metal dichalcogenides. This approach is especially advantageous for time-resolved ARPES, as electron dynamics over a large momentum range can be accessed with identical measurement conditions.