Three-dimensional topological crystalline insulator without spin-orbit coupling in nonsymmorphic photonic metacrystal  

作　　者：Zhide Yu Lingbo Xia 余智德;夏凌波(School of Physics and Electronics,Hunan University,Changsha 410082,China)

机构地区：[1]School of Physics and Electronics,Hunan University,Changsha 410082,China

出　　处：《Chinese Physics B》2024年第10期282-286,共5页中国物理B（英文版）

基　　金：supported by the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.12104148);the Fundamental Research Funds for the Central Universities(Grant No.531118010565).

摘　　要：By including certain point group symmetry in the classification of band topology,Fu proposed a class of threedimensionaltopological crystalline insulators(TCIs)without spin-orbit coupling in 2011.In Fu’s model,surface states(ifpresent)doubly degenerate atГandM when time-reversal and C_(4) symmetries are preserved.The analogs of Fu’s modelwith surface states quadratically degenerate atM are widely studied,while surface states with quadratic degeneracy atГare rarely reported.In this study,we propose a three-dimensional TCI without spin-orbit coupling in a judiciously designednonsymmorphic photonic metacrystal.The surface states of photonic TCIs exhibit quadratic band degeneracy in the(001)surface Brillouin zone(BZ)center(Гpoint).The gapless surface states and their quadratic dispersion are protected by C4and time-reversal symmetries,which correspond to the nontrivial band topology characterized by Z_(2)topological invariant.Moreover,the surface states along lines fromГto the(001)surface BZ boundary exhibit zigzag feature,which is interpretedfrom symmetry perspective by building composite operators constructed by the product of glide symmetries with timereversalsymmetry.The metacrystal array surrounded with air possesses high order hinge states with electric fields highlylocalized at the hinge that may apply to optical sensors.The gapless surface states and hinge states reside in a cleanfrequency bandgap.The topological surface states emerge at the boundary of the metacrystal and perfect electric conductor(PEC),which provide a pathway for topologically manipulating light propagation in photonic devices.

关 键 词：topological crystalline insulator nonsymmorphic photonic metacrystal 

分 类 号：O469[理学—凝聚态物理]