scholarly journals Prediction of topological crystalline insulators and topological phase transitions in two-dimensional PbTe films

2017 ◽  
Vol 19 (43) ◽  
pp. 29647-29652 ◽  
Author(s):  
Yi-zhen Jia ◽  
Wei-xiao Ji ◽  
Chang-wen Zhang ◽  
Ping Li ◽  
Shu-feng Zhang ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Three Dimensional ◽  
Topological Phases ◽  
Topological Phase ◽  
Two Dimensional ◽  
Topological Crystalline Insulators ◽  
Topological Phase Transitions

Topological phases, especially topological crystalline insulators (TCIs), have been intensively explored and observed experimentally in three-dimensional (3D) materials.

scholarly journals Observing multifarious topological phase transitions with real-space indicator

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yong-Heng Lu ◽  
Yao Wang ◽  
Feng Mei ◽  
Yi-Jun Chang ◽  
Hang Zheng ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Three Dimensional ◽  
Real Space ◽  
Second Order ◽  
Topological Phases ◽  
Topological Phase ◽  
Edge States ◽  
Direct Writing ◽  
Topological Features ◽  
Topological Phase Transitions

Abstract First- and second-order topological phases, capable of inherent protection against disorder of materials, have been recently experimentally demonstrated in various artificial materials through observing the topologically protected edge states. Topological phase transition represents a new class of quantum critical phenomena, which is accompanied by the changes related to the bulk topology of energy band structures instead of symmetry. However, it is still a challenge to directly observe the topological phase transitions defined in terms of bulk states. Here, we theoretically and experimentally demonstrate the direct observation of multifarious topological phase transitions with real-space indicator in a single photonic chip, which is formed by integration of 324 × 33 waveguides supporting both first- and second-order topological phases. The trivial-to-first-order, trivial-to-second-order and first-to-second-order topological phase transitions signified by the band gap closure can all be directly detected via photon evolution in the bulk. We further observe the creation and destruction of gapped topological edge states associated with these topological phase transitions. The bulk-state-based route to investigate the high-dimensional and high-order topological features, together with the platform of freely engineering topological materials by three-dimensional laser direct writing in a single photonic chip, opens up a new avenue to explore the mechanisms and applications of artificial devices.

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