Topological phase transition of two-dimensional topological polaritons

Abstract

Topological phase transitions of a two-dimensional topologically nontrivial polaritonic system are studied. A generic model of semiconductor excitons strongly coupled with tailored photonic modes is considered. We introduce a pseudospin operator, measuring the polariton polarization between photonic-like and excitonic-like. The associated pseudospin spectrum and pseudospin Chern numbers are calculated. It is shown that the pseudospin Chern number phase diagram exhibits certain features resembling the topological phase of quantum-spin-Hall-like. Moreover, a series of topological phase transitions may occur with the closing of the bulk energy gap or the pseudospin spectrum gap. In a tight-binding form, the edge-mode simulation is done numerically to confirm the analytically results.

Electronic Quantum Materials Simulated with Artificial Model Lattices

“…The resulting quasi-particle (or excitation) of interest is hence an exciton-polariton . The geometry of the array of semiconductor pillars defines the lattice with lattice sites and hopping barriers for the exciton polaritons. − The de Broglie wavelength of exciton polaritons is large and is used to control hopping and interaction in the lattice. Exciton-polariton lattices are very powerful quantum simulators and could simulate the effects of lattice geometry on the band structure, from the single-particle regime ,− to that of (strong) interactions. − In the limit that exciton-polaritons are nearly photons, we deal with purely photonic lattices, which also have shown strong potential for quantum simulation. ,, …”