PMID- 32441985
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20200525
IS  - 1079-7114 (Electronic)
IS  - 0031-9007 (Linking)
VI  - 124
IP  - 18
DP  - 2020 May 8
TI  - Direct Observation of Flatband Loop States Arising from Nontrivial Real-Space
      Topology.
PG  - 183901
LID - 10.1103/PhysRevLett.124.183901 [doi]
AB  - Topological properties of lattices are typically revealed in momentum space using
      concepts such as the Chern number. Here, we study unconventional loop states,
      namely, the noncontractible loop states (NLSs) and robust boundary modes,
      mediated by nontrivial topology in real space. While such states play a key role 
      in understanding fundamental physics of flatband systems, their experimental
      observation has been hampered because of the challenge in realizing desired
      boundary conditions. Using a laser-writing technique, we optically establish
      photonic kagome lattices with both an open boundary by properly truncating the
      lattice, and a periodic boundary by shaping the lattice into a Corbino geometry. 
      We thereby demonstrate the robust boundary modes winding around the entire edge
      of the open lattice and, more directly, the NLSs winding in a closed loop akin to
      that in a torus. We prove that the NLSs due to real-space topology persist in
      ideal Corbino-shaped kagome lattices of arbitrary size. Our results could be of
      great importance for our understanding of the singular flatbands and the
      intriguing physics phenomenon applicable for strongly interacting systems.
FAU - Ma, Jina
AU  - Ma J
AD  - The MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics
      Institute and School of Physics, Nankai University, Tianjin 300457, China.
FAU - Rhim, Jun-Won
AU  - Rhim JW
AD  - Department of Physics and Astronomy, Seoul National University, Seoul 08826,
      Korea.
AD  - Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 
      08826, Korea.
FAU - Tang, Liqin
AU  - Tang L
AD  - The MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics
      Institute and School of Physics, Nankai University, Tianjin 300457, China.
AD  - Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan,
      Shanxi 030006, People's Republic of China.
FAU - Xia, Shiqi
AU  - Xia S
AD  - The MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics
      Institute and School of Physics, Nankai University, Tianjin 300457, China.
FAU - Wang, Haiping
AU  - Wang H
AD  - The MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics
      Institute and School of Physics, Nankai University, Tianjin 300457, China.
FAU - Zheng, Xiuyan
AU  - Zheng X
AD  - The MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics
      Institute and School of Physics, Nankai University, Tianjin 300457, China.
FAU - Xia, Shiqiang
AU  - Xia S
AD  - The MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics
      Institute and School of Physics, Nankai University, Tianjin 300457, China.
AD  - Engineering Lab for Optoelectronic Technology and Advanced Manufacturing, Henan
      Normal University, Xinxiang, 453007, China.
FAU - Song, Daohong
AU  - Song D
AD  - The MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics
      Institute and School of Physics, Nankai University, Tianjin 300457, China.
AD  - Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan,
      Shanxi 030006, People's Republic of China.
FAU - Hu, Yi
AU  - Hu Y
AD  - The MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics
      Institute and School of Physics, Nankai University, Tianjin 300457, China.
AD  - Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan,
      Shanxi 030006, People's Republic of China.
FAU - Li, Yigang
AU  - Li Y
AD  - The MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics
      Institute and School of Physics, Nankai University, Tianjin 300457, China.
FAU - Yang, Bohm-Jung
AU  - Yang BJ
AD  - Department of Physics and Astronomy, Seoul National University, Seoul 08826,
      Korea.
AD  - Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 
      08826, Korea.
AD  - Center for Theoretical Physics (CTP), Seoul National University, Seoul 08826,
      Korea.
FAU - Leykam, Daniel
AU  - Leykam D
AD  - Center for Theoretical Physics of Complex Systems, Institute for Basic Science,
      Daejeon 34126, Republic of Korea.
FAU - Chen, Zhigang
AU  - Chen Z
AD  - The MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics
      Institute and School of Physics, Nankai University, Tianjin 300457, China.
AD  - Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan,
      Shanxi 030006, People's Republic of China.
AD  - Department of Physics and Astronomy, San Francisco State University, San
      Francisco, California 94132, USA.
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Phys Rev Lett
JT  - Physical review letters
JID - 0401141
SB  - IM
EDAT- 2020/05/23 06:00
MHDA- 2020/05/23 06:01
CRDT- 2020/05/23 06:00
PHST- 2019/11/01 00:00 [received]
PHST- 2020/04/16 00:00 [accepted]
PHST- 2020/05/23 06:00 [entrez]
PHST- 2020/05/23 06:00 [pubmed]
PHST- 2020/05/23 06:01 [medline]
AID - 10.1103/PhysRevLett.124.183901 [doi]
PST - ppublish
SO  - Phys Rev Lett. 2020 May 8;124(18):183901. doi: 10.1103/PhysRevLett.124.183901.