Speaker: Xiao HU 胡 暁
International Center for Materials Nanoarchitectonics (WPI-MANA)
National Institute for Materials Science (NIMS), Tsukuba, Japan
Honeycomb lattice has played an important role in the course of fostering topology physics as known from the Haldane model and the Kane-Mele model . Recently, we proposed a new way to derive nontrivial topology based on honeycomb structure with time-reversal symmetry. The first example is to achieve a topological photonic crystal made of dielectric materials such as silicon . We identify a pseudospin degree of freedom in electromagnetic (EM) modes associated with C6v crystalline symmetry, and show that nontrivial topology is induced by photonic p-d band inversion. Recent microwave experiments confirm our theory [3,4]. The idea can be extended to phononic systems, physical waves, and electronic systems. We investigate graphene with detuned nearest-neighbor hopping energy or nano-hole arrays, and find in the latter case topological edge/interface states protected by energy gap over 1eV [5,6,7]. Recent progresses and perspectives of the present approach will be discussed.
 H.-M. Weng, R. Yu, X. Hu, X. Dai and Z. Fang, Adv. Phys. 64, 227 (2015).
 L.-H. Wu and X. Hu, Phys. Rev. Lett. 114, 223901 (2015).
 Y.-T. Yang, X. Hu and Z.-H. Hang, Phys. Rev. Lett. 120, 217401 (2018).
 Y. Li, H. Chen and X. Hu, arXiv:1801.04395.
 L.-H. Wu and X. Hu, Sci. Rep. 6, 24347 (2016).
 T. Kariyado and X. Hu, Sci. Rep. 7, 16515 (2017).
 T. Kariyado, Y.-C. Jiang, H.-X. Yang and X. Hu, arXiv:1801.03115.
Time & Date: 15:00pm, June 13 (Wedn.), 2018
Venue: Rm. N306, UCAS Teaching Building [View Map]