The 154th AMCP Open Seminar

Tuesday, June 16, 2020, 11:00-12:00

National Institute for Materials Science (NIMS)
Sengen Main Bldg. 8F Middle Seminar Room
※Non-NIMS staff can only participate online.

Pre-registration is not required.
For inquiries, please contact the Administrative Office.
This lecture is open to the public. Your participation is strongly encouraged.

For participation in online, please apply by email to the Administration Office by the day before.
※Audio and video recordings are prohibited.

YAJI Koichiro, Senior Researcher, Synchrotron X-ray Group

Optical spin control revealed by spin- and angle-resolved photoemission spectroscopy

 In the standard model of strongly spin-orbit coupled (SOC) systems, such as topological insulators, the "total" spin is locked to the momentum of an electron. In the present study, we have investigated the SOC surface states of Bi and Bi₂Se₃ with spin- and angle-resolved photoemission spectroscopy using a vacuum ultraviolet laser. The observed spin polarization was inverted upon switching the light polarization from p to s. This indicates that the electronic states are described as the linear combination of symmetric and anti-symmetric states coupled to mutually opposite spins. Moreover, rotating the electric-field vector of the incident linearly polarized light leads to simultaneous excitation of the symmetric and anti-symmetric states, resulting in the three-dimensional spin-vector rotation in the photoemission process due to the spin interference. We demonstrated that the use of the polarization-variable laser offers optical spin control of photoexcited electrons.