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arXiv · 1901.01937

Tunable three-way valley Hall energy-splitter: venturing beyond graphene-like structures

Mehul P. Makwana·Gregory J. Chaplain
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Abstract

Strategically combining four structured domains creates the first ever three-way topological energy-splitter; remarkably, this is only possible using a square, or rectangular, lattice, and not the graphene-like structures more commonly used in valleytronics. To achieve this effect, the two mirror symmetries, present within all fully-symmetric square structures, are broken; this leads to two nondistinct interfaces upon which valley-Hall states reside. These interfaces are related to each other via the time-reversal operator and it is this subtlety that allows us to ignite the third outgoing lead. The geometrical construction of our structured medium allows for the three-way splitter to be adiabatically converted into a wave steerer around sharp bends. Due to the tunability of the energies directionality by geometry, our results have far-reaching implications for applications such as beam-splitters, switches and filters across wave physics.

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Mehul P. Makwana, Gregory J. Chaplain. 2019-01-07. Tunable three-way valley Hall energy-splitter: venturing beyond graphene-like structures. https://doi.org/10.1103/physrevapplied.15.054056

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