Thermally tunable phonon-plasmon polariton modes at hexagonal boron nitride (hBN) and indium antimonide (InSb) interfaces

This work examines the propagation of thermally tunable phonon-plasmon modes at the interfaces of hexagonal boron nitride (hBN) and isotropic indium antimonide (InSb). Both theoretical modeling and numerical simulations are carried out to analyze the effect of temperature on surface wave behavior. hBN is realized as a polar material via the Lorentzian model, while InSb is modeled as a temperature-sensitive material (TSM) in the framework of Drude's model. The possible plasmon-phonon polaritonic interactions are studied for the TSM-elliptic type interface and TSM-hyperbolic type interface. It is reported that by varying the temperature, the surface modes can be tuned for the lower and upper Reststrahlen (RS) bands of hBN. The dispersion curve, effective mode index, propagation length, and phase speed are computed for each case under different temperatures. It is concluded that the hBN-InSb-based phonon-plasmon polariton modes are actively tuned by changing the external temperature in the lower and upper RS bands. Surface waves propagating across the interface can be modulated from the terahertz (THz) region to the infrared (IR) region by changing the temperature of InSb. This study will help researchers to design innovative thermo-optical sensors, plasmonic platforms, detectors, and surface waveguides in the THz and IR regions.