Content of research

Existing semiconductor devices operate through the electric charge of electrons. In addition to the electric charge, an electron also has the other property of spin, which is a magnetic property. The electron spin in a solid can be aligned in a certain direction (Fig. 1a) or rotated about a specific axis (Fig. 1bc), depending on the situation. The key to realizing next-generation electronic devices is to control such electron spin in semiconductor devices. In this study, we used indium-, gallium-, and arsenic-based field-effect transistors (Fig. 2) and performed electrical measurements in a cryogenic environment (absolute temperature of 20 mK) using a dilution refrigerator (Fig. 3). In this way, we were able to precisely determine for the first time the spin-orbit interaction coefficient, which is necessary to control electron spin (Fig. 4).

Potential for social implementation

• ・Field-effect spin transistor
• ・Quantum computers
• ・Ultra-low power logic devices
• ・Next-generation electron spin devices

Appealing points to industry and local governments

The spin-orbit interaction coefficient is a measure of the ease with which electron spin can be controlled and manipulated using gates, but its exact value in any semiconductor used to be unknown. This achievement will make it possible to apply semiconductor engineering methods to the future development of devices such as those listed on the left, which will lead to a significant reduction in the cost and time required for device development.