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The 377th forum: Non-Abelian band topology

Date: 2019-11-14
Time: 10:00
Venue: M236
Speaker: Dr. QuanSheng Wu



2008-2013    Ph.D, Institute of Physics, Chinese Academy of Sciences 中国科学院物理研究所
2004-2008    B.S. Physics, Beijing Normal University 北京师范大学
2003-2004    B.S. College of Information Science and Technology, 北京师范大学
2017.09-Now       Postdoctoral ,École polytechnique fédérale de Lausanne (EPFL) 瑞士联邦理工学院(洛桑)
2015.01-2017.08   Postdoctoral,  Eidgenössische Technische Hochschule Zürich (ETHZ) 瑞士联邦理工学院(苏黎世)
2013.07-2014.12  Research Assistant, Institute of Applied Physics and Computational Mathematics (IAPCM) 北京应用物理与计算数学研究所


Electron energy bands of crystalline solids generically exhibit degeneracies called band-structure nodes. Here, I would like to introduce non-Abelian topological charges [1] that characterize line nodes inside the momentum space of crystalline metals with space-time inversion (PT) symmetry and with weak spin-orbit coupling. It's shown that these are quaternion charges, similar to those describing disclinations in biaxial nematics. Starting from two-band considerations, I will also introduce a complete many-band description of nodes in the presence of PT and mirror symmetries, which allows us to investigate the topological stability of nodal chains in metals. The non-Abelian charges put strict constraints on the possible nodal-line configurations. This analysis goes beyond the standard approach to band topology and implies the existence of one-dimensional topological phases not present in existing classifications. At the end of this talk, I would like to introduce our open-source software WannierTools [2] briefly.


[1] QuanSheng Wu, Alexey A. Soluyanov, Tomáš Bzdušek, Non-Abelian band topology in noninteracting metals, Science 365, 1273 (2019)

[2] QuanSheng Wu, ShengNan Zhang, Hai-Feng Song, Matthias Troyer, and Alexey A. Soluyanov, WannierTools: An open-source software package for novel topological materials, Computer Physics Communications 224, 405 (2018)

邀 请 人:王志俊(电话:8264 9070)

联 系 人:李园园(电话:8264 9364)