Artificial phonon-plasmon polariton at the interface of piezoelectric metamaterials and semiconductors

We studied a polariton formed at the interface between a piezoelectric metamaterial and a semiconductor or metallic metamaterial. The piezoelectric metamaterial consists of periodically poled domains that has an optical phonon frequency in the terahertz ranges. When the piezoelectric metamaterial is in contact with a semiconductor or metallic metamaterial substrate, the coupling between the metamaterial's optical phonons and the substrate's plasmons results in the formation of a type of artificial surface polariton: phonon-plasmon polariton. The effective dielectric constant of the piezoelectric metamaterial is theoretically derived and the strong dispersion and band gap phenomena of the phonon-plasmon polariton are investigated. The artificial surface phonon-plasmon polariton may offer opportunities in optical science such as acoustic excitation of surface plasmons and vice versa.