Phys.org November 7, 2018
Researchers in Japan developed a terahertz pulse generator that delivered ultra-short and highly intense terahertz pulses across a pair of gold antennas. The pulses created an electric field in the material composed of germanium, antimony and tellurium (GST) sample, comparable to that of an electrically switched device. It greatly reduced the heat diffusion because of the extremely short duration of terahertz pulses enabling fine control over the rate and direction of GST crystallization. After a certain point when terahertz pulses were increased, crystal conductivity rapidly sped up instead of rising in line with the increase in terahertz strength. The researchers hypothesize that electrons jumping between states in the crystal added an unexpected source of heat to the system, boosting crystallization. The findings show how nanoscale and direction-controlled growth of crystals in GST can be achieved and the phenomenon should assist in the design of new devices and ultimately realize the fast and stable digital information handling potential this material…read more. Open Access TECHNICAL ARTICLE
Terahertz electromagnetic pulse controlling the physical structure of data-storage material. Credit: Kyoto University/Hirori Lab