catalog of topological flat bands and the applications

报告题目   catalog of topological flat bands and the applications
报告人   徐远锋 研究员
报告人单位   浙江大学
报告时间   2023-11-13 16:00:00
报告地点   物质科研b楼0804会议室
主办单位   合肥微尺度物质科学国家研究中心、国际功能材料量子设计中心


  flat bands in crystalline materials come in two kinds: atomically flat and topologically flat. flat atomic bands are topologically trivial and commonly exist in layered materials and heavy fermion systems. topological flat bands were recently discovered in twisted 2d materials, where the coexistence of nontrivial band topology and strong electronic correlation manifests kinds of exotic quantum phases, such as quantum anomalous hall effect, magnetism, correlated insulating states, and superconductivity. in addition, a few 2d line-graph lattices with s orbitals were also proposed to have topological flat bands in the tight-binding approximation. compared with the twisted superlattice, stoichiometric flat-band materials are much easier to synthesize and have a larger carrier density. here i’ll introduce a general construction of flat bands in both 2d and 3d crystals. using the magnetic topological quantum chemistry theory, we have a full classification of band topologies in paramagnetic and magnetic materials both with and without spin-orbit coupling. these advantages enable a complete understanding of flat-band features in most materials. by analyzing the geometry and symmetry properties, a high-throughput search and classification of topological flat-band materials were performed to build a material database.we further investigate a set of kagome compounds and show that their flat band are the result of more convoluted properties than simple kagome flat bands. we present a lego-like principle to explain the existence of flat bands in many kagome metals, starting from a single building block, fege.




catalog of topological flat bands and the applications-皇冠体育平台