Dispersion properties of van der Waals phonon polaritons modulated by Weyl semimetals

Surface phonon polaritons (SPhP) have attracted extensive attention and been investigated as an alternative constituent for mid-infrared (MIR) nanophotonic applications, with a possibility to solve the intrinsic loss problem of plasmonics. SPhPs arise in polar dielectrics due IR-active resonances, leading negative permittivity within Reststrahlen band. Though own great potential process enhancing interaction between light matter infrared region, there are still limited enhancement optical fields fixed resonance band because existing Moreover, active manipulating MIR range remains elusive. There has significant progress natural vdW crystal heterostructures, which characterized by anisotropic polaritonic response, elliptical, hyperbolic, or biaxial dispersions. Among these structures, PhPs hyperbolicity α-MoO<sub>3</sub>are particular interest, not only strong field confinement, low losses, long lifetimes, but also in-plane dispersion. A heterostructure composed van der Waals material (a-MoO<sub>3</sub>) Weyl semimetal (WSM) proposed study tunability SPhPs. The controlment can exhibit more degrees freedom, yet addressed. Under incident condition transverse magnetic (TM) wave, reflection coefficient distribution heterogeneous system accurately solved 4×4 transfer matrix method (TMM), dispersion properties described detail. Variation spectrum azimuthal angle α-MoO<sub>3</sub> thickness presented. research results indicate that mode hybridization manipulation be realized through azimuth a-MoO<sub>3</sub>. More importantly, Fermi level WSM enable dynamic curve adjustment, depends on change external temperature. Equal-frequency curves hybridized SPhP at different levels demonstrated. By chemically changing Femi α-MoO<sub>3</sub>, topology polariton isofrequency surfaces transforms from open closed shapes result hybridization. Therefore, our is helpful further optimize design optoelectronic devices based materials, good application prospects heat radiation biosensing.