• Physics 16, s100
A photonic model of graphene hosts never-before-seen “twig” edge states—which may present new avenues for realizing topological phases in graphene-like supplies.
Graphene and graphene-like supplies can host—at their edges—localized states whose properties can differ dramatically from these of bulk states. Three kinds of edge states have been established in these supplies—zigzag, bearded, and armchair—named after their geometry. Now Daohong Track of Nankai College in China and collaborators have used a graphene-like photonic crystal to display the potential of a fourth edge, known as twig, with unique topological options. The researchers recommend that twig edge states may exist in different honeycomb-lattice constructions, broadening the choices for realizing topologically protected power transport through edge states in supplies .
The end result builds on the workforce’s earlier demonstration of a laser-based method for “writing” an arbitrarily formed array of waveguides in a crystal . Guided by simulations, they designed a honeycomb construction with twig-shaped edges and predicted that such edges would host nontrivial states. They then realized the construction as a honeycomb lattice of waveguides with a 32-µm lattice spacing. Lastly, they used a laser to couple gentle into the twig edge states and studied how the sunshine propagated by means of the waveguides. The outcomes present the twig edge states have each topological and “flat band” options—two substances that may give rise to intriguing phases of matter.
Track says that, along with the three beforehand recognized edges, the twig edge varieties an entire foundation for describing all doable edge sorts in honeycomb lattices—any arbitrary edge might be described as a mixture of these 4 sorts. As such, the brand new work may assist in creating a normal framework for describing edge states in graphene-like supplies, which could possibly be used to create and research new topological phases.
Matteo Rini is the Editor of Physics Journal.