Electronics has relied on the electron charge, while the electron spin has emerged as an additional functional degree of freedom, leading to the development of spintronics. Recent advances in quantum science and semiconductor technologies have further accelerated interest in spin-dependent phenomena and their integration into next-generation devices. Spin- and angle-resolved photoemission spectroscopy (SARPES) enables direct measurement of energy-, momentum-, and spin-resolved electronic structures, providing unique insight into the microscopic origins of material properties. Continuous advances in SARPES instrumentation—including high-efficiency spin detectors, high-brilliance photon sources, improved energy and momentum resolution, and time-resolved techniques—have significantly broadened its applicability. Consequently, SARPES has become a powerful and widely used tool for investigating magnetic materials, Rashba-split systems, topological materials, superconductors, and complex interfaces. This special issue presents recent methodological advances in SARPES together with representative applications, offering an overview of current research frontiers and future directions.
Yaji et al. (Thu,) studied this question.