正文
Unconventional magnetism and spontaneous spin-orbit ordering
报告人：Congjun Wu，University of California
时间：7月12日（周三）15:00
单位：
北京师范大学物理系
地点：物理楼106
报告人：姚秋玲，中科院高能研所
时间：7月12日（周三）15:00
单位：中科院高能物理研究所
地点：计算中心二楼会议室
CASTOR是一套由CERN开发的分级存储管理系统，用于存储海量物理数据，实现在磁盘和磁带不同级别的存储介质之间进行文件的迁移。CASTOR中的文件可通过RFIO（远程文件输入/输出）协议采用命令行或函数调用的方式进行访问。CASTOR在CERN和IHEP中已经应用很长时间。
6
Engineering and probing topological properties of Dirac semimetal films by asymmetric charge transfer
报告人：Kyungwha Park，VirgininaTech
时间： 7月13日（周四）14:00
单位：中科院高能物理研究所
地点：M楼830
Dirac and Weyl semimetals have been under intense investigation due to topologically protected Weyl nodes and Fermi arc states connecting the node projections at a surface. Recently, Na3Bi, Cd3As2, PtSe2, and PtTe2 have been experimentally confirmed to be Dirac semimetals (DSMs), where the Dirac nodes are stabilized by crystal rotational symmetries. In the presence of an external magnetic field, the DSMs become Weyl semimetals. In heterostructures involving DSMs, charge transfer may occur at the interfaces, which can be used to probe and control their bulk and surface topological properties through surface-bulk connectivity. Here we demonstrate that despite a band gap in thin DSM films, asymmetric charge transfer at the surface enables one to accurately identify locations of the Dirac-node projections from gapless band crossings and to examine and engineer properties of the topological Fermi-arc surface states connecting the projections, by simulating adatom-adsorbed DSM films using a first-principles method and by comparing with the effective model. We show that as the amount of charge transfer varies, unique spin textures near the projections and a separation between the Fermi-arc states change. Our results can be observed by top or bottom gating without adatoms.
7
Topological Band Theory for Non-Hermitian Hamiltonians
报告人：沈汇涛，MIT
时间：7月13日（周四）15:30
单位：中科院物理研究所
地点：M楼830
Recently, there have been many experimental realizations of the non-Hermitian Hamiltonians in both open quantum systems and classical wave systems with gain or loss. I will show that the non-Hermitian Hamiltonians host topological classification very differently from the Hermitian ones. There are non-trivial generalizations of the Chern number in two dimensions, and a new classification in one dimension, which is based on the energy dispersion rather than the Bloch state.
I will first start talking about the basics of the non-Hermitian Hamiltonians, and then introduce the topological band theory, by explicitly showing the topological invariants. I will also talk about the non-Hermitian bulk-edge correspondence as well as the phase diagram for topological phase transitions, if there is time.
8
Disorder Effects on Surface States in Topological Materials
报告人：Sergey Savrasov，University of California Davis.
