R&D: Role of Oxygen in Crystallization of Monatomic Phase-Change Material Sb: Insights From First Principles

SSRN has published an article written by Yuemei Sun, Li Yuan, Xiaoqin Zhu, Weihua Wu, Yifeng Hu, Jiangsu University of Technology, and Zhitang Song, Chinese Academy of Sciences (CAS) – Shanghai Institute of Microsystem and Information Technology.

Abstract: “The crystalline–amorphous–crystalline transition process of oxygen-tuned Sb phase-change material has been obtained by employing ab initio molecular dynamic calculations. By analyzing the local atomic arrangement and electron structure of SbO system, the intrinsic mechanism is explored to comprehend the material function: (1) ultrafast crystallization and difficulty in creating glassy state of pure Sb material might be caused by the resonance bonding of linear arrangement Sb atoms in rhombohedral phase; (2) the impurity oxygen atoms break the medium and long-range linear arrangement of the Sb network by steric effects and change the electronic structure of these Sb atoms bonded to oxygen atoms from resonance bonding to semiconductor-like bonding, i.e. the appearance of the band gap and the increase of electronic localization, due to the high electronegativity of oxygen. These factors set an effective barrier for crystallization and improve the amorphous stability, and thus data retention. The present research and scheme provide important insights into the engineering and manipulation of monatomic phase-change material, through first-principles calculations towards nonvolatile phase change memory.“