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Nucleation Dynamics of Phase‐Change Memory Materials: Atomic Motion and Property Evolution
Author(s) -
Chen Nian-Ke,
Liu Yu-Ting,
Wang Xue-Peng,
Li Xian-Bin
Publication year - 2021
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.202000441
Subject(s) - nucleation , delocalized electron , recrystallization (geology) , chemical physics , materials science , atom (system on chip) , molecular dynamics , electron , amorphous solid , phase transition , condensed matter physics , physics , crystallography , chemistry , thermodynamics , computational chemistry , computer science , quantum mechanics , paleontology , biology , embedded system
Reversible phase transitions between crystalline and amorphous phases of phase‐change memory (PCM) materials are the physical basis of PCM. Applications of PCM in multilevel memory, in‐memory computing, and neuromorphic computing require a precise control of material's structure/property to achieve signals beyond binary (0/1), where recrystallization is the key process because it is smooth compared with violent amorphization. By molecular dynamic simulations and electronic structure analyses based on density functional theory, nucleation dynamics during recrystallization are investigated from the point of view of atomic motions and property evolutions. Atomic motions are examined individually rather than statistically. According to the results, an atomic picture of the growth of the nucleus is described in detail, where the competition between the potential seeds of nucleus plays a critical role. The electron polarization during recrystallization is mapped to the linearly aligned atom chains. Further analyses of the Born effective charge confirm the delocalization of the electrons in the atom chains. Also, a large p ‐orbital‐axial Born effective charge is observed in long‐range atom chains, which suggests a kind of resonance enhancement of electronic delocalization. These dynamics of nucleation in recrystallization provide references for the fine control of PCM performances.