报  告 人：张东波  教授  北京师范大学核科学与技术学院

报告时间：2021年7月14日上午9:30-11:00

报告地点：基础楼1603会议室

主办单位：数理系、科技处

报告内容：Often, low dimensional systems such as graphene are of superior structural flexibility and exhibit excellent electromechanical response, i.e., the coupling of electronic properties with structural deformation. This indicates that novel electronic properties can be obtained by strain manipulation on electronic states. The relevant studies have led to an emergent area, i.e., strain engineering. However, theoretical research such as first-principles calculation mainly focuses on homogeneous strain and the exploration of inhomogeneous strain is rare. Largely, this is because that inhomogeneous strain destroys the translational symmetry of crystal, which the traditional approaches of electronic energy band calculations rely on. We developed a new approach of energy band calculation named as Generalized Bloch Theorem, coupled with self-consistent charge density-functional tight-binding. This new approach can effectively deal with low dimensional materials under torsional or bending deformations.

In this talk, I will introduce the essential idea of the generalized Bloch theorem and illustrate application of it in low dimensional materials with several examples, including strain induced half-metallicity in graphene nanoribbon, the modulation of dopant distribution in silicon nanowires by twisting.

个人简介：D.-B. Zhang obtained his PhD in 2010 and was a postdoc associate from 2011 to 2013 at the University of Minnesota, USA. In 2014 he was awarded the “Thousand Youth Talents Plan” and joined the Beijing Computational Science Research Center as an Assistant Professor. Since 2018, he joined Beijing Normal University as a Professor in condensed matter physics. His research is essentially in the area of computational materials science, with focus on thermal properties of materials under extreme conditions. He is also interested in the strain engineering of low dimensional materials. He published more than 40 peer-reviewed papers in Physical Review Letters, National Science Review, Physical Review B, and so on.