Topological Phonon Polaritons for Thermal Radiation Control

Topological phonon polaritons (TPhPs) are highly localized edge modes that can achieve a strong confinement of electromagnetic waves and are topologically protected to be immune to impurities and disorder. In this paper, we theoretically study the topological phonon polaritons (TPhPs) in one-dimensional (1D) dimerized silicon carbide (SiC) nanoparticle (NP) chains, as an extension of the celebrated Su-Schrieffer-Heeger (SSH) model. We analytically calculate the band structure and complex Zak phase for such chains by taking all near-field and far-field interactions into account. It is found that the 1D dimerized chain supports nontrivial topological states as long as the dimeriza-tion parameter β > 0.5 and the long-range interactions are weak, although the system is non-Hermitian. By analyzing the distribution of eigenmodes and their participation ratios (PRs), we comprehensively study the effects of disorder on the band structure and midgap modes. We reveal that such TPhPs are very robust under high-degree disorders and even enhanced by the disorder. Through a finite-size scaling analysis, we show this enhancement can be attributed to Anderson localization scheme. These topological phonon polaritonic states provide an efficient interface for thermal radiation control in the mid-infrared.