scholarly journals The nonmodular topological phase and phase singularities

2011 ◽  
Vol 375 (41) ◽  
pp. 3562-3569
Author(s):  
Rajendra Bhandari
Keyword(s):  
Topological Phase ◽  
Phase Singularities

scholarly journals Knotted Topological Phase Singularities of Electromagnetic Field

2008 ◽  
Vol 50 (5) ◽  
pp. 1071-1076 ◽  
Author(s):  
Ren Ji-Rong ◽  
Zhu Tao ◽  
Mo Shu-Fan
Keyword(s):  
Electromagnetic Field ◽  
Topological Phase ◽  
Phase Singularities

scholarly journals Topological phase singularities in atomically thin high-refractive-index materials

2021 ◽  
Author(s):  
Georgy Ermolaev ◽  
Kirill Voronin ◽  
Denis Baranov ◽  
Vasyl Kravets ◽  
G. Tselikov ◽  
...  
Keyword(s):  
Refractive Index ◽  
Mechanical Stability ◽  
Optical Design ◽  
High Refractive Index ◽  
Phase Changes ◽  
Refractive Index Sensor ◽  
Perfect Absorber ◽  
Topological Phase ◽  
Rapid Phase ◽  
Phase Singularities

Abstract Atomically thin transition metal dichalcogenides (TMDCs) present a promising platform for numerous photonic applications due to excitonic spectral features, possibility to tune their constants by external gating, doping, or light, and mechanical stability. Utilization of such materials for sensing or optical modulation purposes would require a clever optical design, as by itself the 2D materials can offer only a small optical phase delay – consequence of the atomic thickness. To address this issue, we combine films of 2D semiconductors which exhibit excitonic lines with the Fabry-Perot resonators of the standard commercial SiO2/Si substrate, in order to realize topological phase singularities in reflection. Around these singularities, reflection spectra demonstrate rapid phase changes while the structure behaves as a perfect absorber. Furthermore, we demonstrate that such topological phase singularities are ubiquitous for the entire class of atomically thin TMDCs and other high-refractive-index materials, making it a powerful tool for phase engineering in flat optics. As a practical demonstration, we employ PdSe2 topological phase singularities for a refractive index sensor and demonstrate its superior phase sensitivity compared to typical surface plasmon resonance sensors.

scholarly journals Topological phase transition between a normal insulator and a topological metal state in a quasi-one-dimensional system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Milad Jangjan ◽  
Mir Vahid Hosseini
Keyword(s):  
Phase Transition ◽  
Dimensional System ◽  
Inversion Symmetry ◽  
Topological Phase ◽  
Edge States ◽  
Zero Energy ◽  
One Dimensional ◽  
Topological Phase Transition ◽  
Metal State ◽  
Topological Metal

AbstractWe theoretically report the finding of a new kind of topological phase transition between a normal insulator and a topological metal state where the closing-reopening of bandgap is accompanied by passing the Fermi level through an additional band. The resulting nontrivial topological metal phase is characterized by stable zero-energy localized edge states that exist within the full gapless bulk states. Such states living on a quasi-one-dimensional system with three sublattices per unit cell are protected by hidden inversion symmetry. While other required symmetries such as chiral, particle-hole, or full inversion symmetry are absent in the system.

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