Related Experiment Video
Updated: Jan 25, 2026

Preparation of Large-area Vertical 2D Crystal Hetero-structures Through the Sulfurization of Transition Metal Films for Device Fabrication
Published on: November 28, 2017
Band structure and topological phase transition of photonic time crystals
Abstract:
We investigate the band structure and topological phase transition of photonic time crystals (PTC)-systems in which the physical parameter varies periodically in time. We find that the topological phase transition of the PTC system can be revealed by the wave vector gap (k-gap) size, which was induced by the temporal refraction and reflection. Interestingly, a temporal zero-averaged refractive index k-gap is obtained when the PTC system includes a dispersive medium. This special k-gap is invariant with modulation time scaling at a given modulation frequency.
Related Concept Videos
Phase Transitions
Phase Transitions: Sublimation and Deposition
Phase Transitions: Melting and Freezing
Ionic Crystal Structures
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Phase Transitions: Vaporization and Condensation
Band Theory
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...

