A Complicated Route from Disorder to Order in Antimony-Tellurium Binary Phase Change Materials

作者：Zheng, Yonghui; Song, Wenxiong; Song, Zhitang^*; Zhang, Yuanyuan; Xin, Tianjiao; Liu, Cheng; Xue, Yuan; Song, Sannian; Liu, Bo; Lin, Xiaoling; Kuznetsov, Vladimir G.; Tupitsyn, Ilya I.; Kolobov, Alexander V.^*; Cheng, Yan^*

来源：Advanced Science, 2023.

DOI：10.1002/advs.202301021

• antimony-tellurium binary materials
• atomic structure
• phase transition mechanism
• phase-change materials
• spherical aberration-corrected transmission electron microscope

The disorder-to-order (crystallization) process in phase-change materials determines the speed and storage polymorphism of phase-change memory devices. Only by clarifying the fine-structure variation can the devices be insightfully designed, and encode and store information. As essential phase-change parent materials, the crystallized Sb-Te binary system is generally considered to have the cationic/anionic site occupied by Sb/Te atoms. Here, direct atomic identification and simulation demonstrate that the ultrafast crystallization speed of Sb-Te materials is due to the random nature of lattice site occupation by different classes of atoms with the resulting octahedral motifs having high similarity to the amorphous state. It is further proved that after atomic ordering with disordered chemical occupation, chemical ordering takes place, which results in different storage states with different resistance values. These new insights into the complicated route from disorder to order will play an essential role in designing neuromorphic devices with varying polymorphisms. @@@ Direct atomic identification technique demonstrates that the ultrafast speed of Sb-Te materials is due to the disordered nature of lattice occupation by different classes of atoms. After atomic ordering with disordered chemical occupation, is a chemical ordering sequence, which brings different storage states with different resistance values.image

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  中国科学院; y; i