Researchers from the Chinese Academy of Sciences and other institutions have developed a new technique to enhance the capabilities of laser-based angle-resolved photoemission spectroscopy (ARPES), a tool used to study the electronic properties of materials. This advancement could have significant implications for the energy sector, particularly in the development and understanding of novel energy materials.
Angle-resolved photoemission spectroscopy (ARPES) is a powerful technique used to probe the energy and momentum of electrons in materials. However, conventional setups have a limitation: they can only capture a small fraction of the full 2π solid angle, which restricts the momentum space that can be explored. This limitation is particularly acute in laser-based ARPES, where the low photon energy further restricts the accessible momentum range despite the ultrahigh resolution.
The researchers, led by X. J. Zhou and colleagues, have introduced a method called bias ARPES. By applying a sample bias, they were able to expand the accessible momentum range and enable full 2π solid angle collection in two dimensions using a 6.994 eV laser source. This technique involves establishing an analytical conversion relation to accurately map the detector angle to the emission angle and the electron momentum in two dimensions. The researchers also developed a precise approach to determine the sample work function, which is critical for the angle-momentum conversion in bias ARPES experiments.
One of the key findings of this study is that energy and angular resolutions are preserved under biases up to 100 V. The researchers also demonstrated that minimizing beam size is crucial for the effectiveness of the technique. Importantly, bias ARPES is effective both near normal and off-normal geometries, allowing flexible access to the Brillouin zone with lower biases. This makes the technique versatile and applicable across a broad photon-energy range.
The practical applications of this research for the energy sector are significant. ARPES is widely used to study the electronic properties of materials, which is crucial for the development of new energy technologies. For example, understanding the electronic structure of materials can aid in the design of more efficient solar cells, better batteries, and improved catalysts for energy conversion and storage. By enhancing the capabilities of laser-based ARPES, this research could accelerate the discovery and development of novel energy materials.
The research was published in the journal Nature Communications, a prestigious open-access journal that publishes high-quality research across all areas of the natural sciences. This study represents a significant advancement in the field of ARPES and has the potential to make a substantial impact on the energy sector.
This article is based on research available at arXiv.