A research group led by Assistant Professor Satoshi KUSABA and Professor Jun TAKEDA at Yokohama National University, Dr. Haw-Wei Lin and Professor Geoff Blake at California Institute of Technology demonstrated that tungsten selenide (WSe2), a kind of transition metal dichalcogenide semiconductor that has attracted attention as a next-generation electronics and valleytronics material, can excite coherent vibrations by irradiating it with broadband terahertz pulses. Furthermore, they found that this excitation process occurs through a sum-frequency process, which is different from the conventional vibration excitation process. As vibrational excitation by sum frequency generation opens up the possibility of vibration control, it is expected to lead to the clarification of the physical properties of layered semiconductors, a promising material for valleytronics applications, and to the control of photoelectric conversion, which is important for the development of devices.

The research results were published in the international scientific journal “Applied Physics Letters” (March 19, 2024) and selected as Editor’s Pick. This research was also supported by a bilateral exchange program and a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS).

Related Link

Terahertz sum-frequency excitation of coherent optical phonons in the two-dimensional semiconductor WSe2
(Applied Physics Letters, RESEARCH ARTICLE| MARCH 19 2024)