报告题目：DFT and TEM guided advances in phase-change materials and memories

　　主讲嘉宾：Prof. Wei Zhang
　　　　　　　CAMP-Nano, Xi’an Jiaotong University

　　活动时间：9月18日（周二）下午14:00

　　活动地点：李薰楼249会议室

　　报告简介：

　　Mobile electronics, the Internet, artificial intelligence, big data and high-performance computing are changing our lives rapidly and profoundly. They also pose, however, a major challenge on data storage and processing: the volume of digital information across the globe doubles every two years, set to reach 44 zettabytes (4.4 × 1010 terabytes) by 2020. A new generation of non-volatile memories that preserve data in the absence of power supply (much like hard disk drives), and at the same time are as fast as dynamic random access memories (DRAMs), is currently being pursued to meet this challenge. Among the competing candidates, phase-change memories (PCMs) are the most mature technology [1, 2], and already start to serve as storage-class memories to boost the computing efficiency. In this talk, I will highlight the indispensable role of density functional theory (DFT) and transmission electron microscopy (TEM) in elucidating the crucial materials properties that enable the application of phase-change chalcogenides in novel memory devices [3-5]. The examples showing in this field could be instructive to other materials-science communities.

　　[1] M. Wuttig & N. Yamada, Phase-change materials for rewriteable data storage. Nat. Mater. 6, 824-832 (2007).

　　[2] W. Zhang & E. Ma, Phase-change memory: Single-element glass to record data. Nat. Mater. (news & views) 17, 654-655 (2018).

　　[3] W. Zhang, et al. Role of vacancies in metal-insulator transitions of crystalline phase-change materials. Nat. Mater. 11, 952-956 (2012).

　　[4] B. Zhang, W. Zhang, et al. Element-resolved atomic structure imaging of rocksalt Ge2Sb2Te5 phase-change material. Appl. Phys. Lett. 108, 191902 (2016).

　　[5] F. Rao, W. Zhang, E. Ma, et al. Reducing the stochasticity of crystal nucleation to enable subnanosecond memory writing. Science 358, 1423-1427 (2017).

　　主讲嘉宾简介：

　　张伟于2004-2010年在浙江大学物理系获得学士与硕士学位，于2011-2015年在德国亚琛工业大学物理系获得博士学位并从事博士后研究。留德期间获得德国博士学位最高荣誉Summa Cum Laude、亚琛工业大学授予的Borchers-Plakette奖章，并被德意志学术交流中心选为“留学德国”代言人。2015年5月加入西安交通大学材料学院微纳中心CAMP-Nano以及金属材料强度国家重点实验室，先后任特聘研究员，教授。主要利用第一性原理计算和电子显微学实验研究相变数据存储材料、低维半导体材料等先进电子材料的基础材料学特性。至今已在Science、Nat Mater、Nat Commun、Adv Mater、PRL/PRB/APL等国际知名学术期刊上发表论文30余篇。

　　欢迎所内职工和研究生前来交流！