Fast and reversible phase transitions in chalcogenide phase-change materials (PCMs), in particular, Ge-Sb-Te compounds, are not only of fundamental interests, but also make PCMs based random access memory (PRAM) a leading candidate for non-volatile memory and neuromorphic computing devices. To RESET the memory cell, crystalline Ge-Sb-Te has to undergo phase transitions firstly to a liquid state and then to an amorphous state, corresponding to an abrupt change in electrical resistance. In this work, we demonstrate a progressive amorphization process in GeSb2Te4 thin films under electron beam irradiation on transmission electron microscope (TEM). Melting is shown to be completely absent by the in situ TEM experiments. The progressive amorphization process resembles closely the cumulative crystallization process that accompanies a continuous change in electrical resistance. Our work suggests that if displacement forces can be implemented properly, it should be possible to emulate symmetric neuronal dynamics by using PCMs.
@article{arxiv.1904.10601,
title = {Progressive amorphization of GeSbTe phase-change material under electron beam irradiation},
author = {Ting-Ting Jiang and Jiang-Jing Wang and Lu Lu and Chuan-Sheng Ma and Dan-Li Zhang and Feng Rao and Chun-Lin Jia and Wei Zhang},
journal= {arXiv preprint arXiv:1904.10601},
year = {2019}
}