Extremely low-frequency phonon material and its temperature- and photo-induced switching effects
Takaya Yoshida, Koji Nakabayashi, Hiroko Tokoro, Marie Yoshikiyo, Asuka Namai, Kenta Imoto, Kouji Chiba, Shin‐ichi Ohkoshi
Abstract
(0.58 THz) in a Rb-intercalated two-dimensional cyanide-bridged Co-W bimetal assembly. This ultralow frequency is attributed to a millefeuille-like structure where Rb ions are very softly sandwiched between the two-dimensional metal-organic framework, and the Rb ions slowly vibrate between the layers. Furthermore, we demonstrate temperature-induced and photo-induced switching of this low-frequency phonon mode. Such an external-stimulation-controllable sub-terahertz (sub-THz) phonon crystal, which has not been reported before, should be useful in devices and absorbers for high-speed wireless communications such as beyond 5G or THz communication systems.