Atomic-Scale Characterizations of Phase Transitions in Ge-Sb-Te Alloys

Tailoring the degree of structural disorder in Ge-Sb-Te alloys is important for the development of non-volatile phase-change memory and neuro-inspired computing. In this talk, I will present the atomic-level details of the multi-fold structural transitions, including crystallization, amorphization, vacancy ordering/disordering induced crystal-crystal transitions, in Ge-Sb-Te alloys by in situ high-resolution transmission electron microscopy experiments and ab initio density functional theory calculations. The impact of atomic ordering on altering the electronic and optical properties of Ge-Sb-Te alloys will be discussed in detail, which is relevant to practical applications. At last, I will also discuss the challenges and progress on atomistic modelling of Ge-Sb-Te alloys at the device scale. References: [1] T.-T. Jiang, X.-D. Wang, J.-J. Wang, H.-Y. Zhang, L. Lu, C. Jia, M. Wuttig, R. Mazzarello, W. Zhang*, E. Ma, In situ characterization of vacancy ordering in Ge-Sb-Te phase-change memory alloys, Fundamental Research DOI: 10.1016/j.fmre.2022.09.010 (2022). [2] Y. Xu, Y.-X. Zhou, X. Wang, W. Zhang*, E. Ma, V.L. Deringer, R. Mazzarello*, Adv. Mater. 34 (2022) 2109139. [3] Y.-X. Zhou, W. Zhang*, E. Ma, V. L. Deringer*, Unlocking device-scale atomistic modelling of phase-change memory materials, arxiv: 2207.14228 (2022)