Since electron spin has a magnetic moment and interacts with the magnetic field through the Zeeman effect, it has been conventionally controlled by external magnetic fields such as for electron spin resonance. Spin-orbit interaction is a relativistic effect that converts an electric field into a magnetic field, and electron spins feel an effective magnetic field dependent on the direction of motion by moving in the electric field. In addition, spin angular momentum and orbital angular momentum are coupled by spin-orbit interaction, and spin up and down electrons are deflected in opposite directions by the spin Hall effect. These features in spin-orbit interaction allow various spin functions based on electrical means without using an external magnetic field. This report reviews the origins of various spin-orbit interactions and their spin-related properties and functions.

Nitride semiconductors are used in the active layers of LEDs and lasers with various emission colors. There are, however, problems with the emission efficiency decreasing at longer wavelength and with increasing current, and it is needed to understand the mechanisms of radiative and non-radiative recombination processes that govern these phenomena. For this purpose, it is important to accurately measure the internal quantum efficiency (the ratio of the number of radiatively-recombined carriers to the total number of recombined carriers), but this is not easy, and there is still argument over the measurement method. In this paper, we will introduce recent progress on the mechanisms of radiative and non-radiative recombination processes in nitride semiconductors and on methods for measuring internal quantum efficiency.

Cu interconnects have been used for more than 20 years by introducing several breakthrough technologies. While R&D to further extend Cu damascene interconnects to the 2 nm node and beyond continues, alternative interconnect metal materials such as ruthenium are being investigated to replace Cu in anticipation of the approaching limit to extend Cu interconnect technology. This paper outlines the major advances that Cu interconnect has made over the past 20 years, and introduces some of the key technologies that are being considered for use in the coming 2 nm generation. Finally, the alternative metal interconnect technologies that are expected to follow the limitations of Cu interconnects will be outlined.

Surface analysis have been indispensable in various industrials for ages and have been developed closely related with industrials in the progress. In this report, some analytical examples are introduced in which the surface analysis works efficiently taking advantage of its intrinsic characteristic. The data acquired is available enough to support the research and developing or solve the issues in industrials.

Optogenetic techniques, in which neural activity can be controlled by irradiating light from outside, have high temporal resolution and are used to understand brain function. In recent years, there has been a growing demand for techniques to irradiate light to multiple specific neurons spread throughout the brain tissue in order to elucidate more advanced brain functions with complex neural networks. However, it is difficult to irradiate specific areas or multiple areas simultaneously using conventional light irradiation techniques such as optical fibers or microscopes, and their use in freely behaving animals is limited. In this paper, we introduce our MicroLED neuroscience probes that can be applied to a deep brain region and a wide area of the cerebral cortex.

With the recent development and expansion of quantum beam analysis techniques, there is a growing need for the analyses under real operating environments, that is, “operando” analyses. This article focuses on operando analyses in mechanical dynamic environments using X-rays and neutrons, and introduces the instrument design for the trial and the obtained results.