Temperature-dependent microwave dielectric permittivity in wurtzite AlN/6H-SiC heterostructures from deep potential molecular dynamics simulations

The microwave (MW) dielectric permittivity of the hybrid of wide-gap semiconductors, such as Wurtzite AlN/6H-SiC mixture (w-AlN/6H-SiC) heterostructures, demonstrates significant enhancement and potential in bulk power and electronic devices due to their superior microwave attenuation properties and excellent thermal resistance. Due to the lack of direct measurement data regarding the microwave attenuation performance of w-AlN/6H-SiC compounds in experiments, herein, we utilized a broad range of theoretical calculations combining with deep potential molecular dynamics simulations to explore the origin of the enhanced microwave attenuation performance of w-AlN/6H-SiC heterostructures at elevated temperatures. Our findings reveal that the microwave dielectric permittivity (MDP) of w-AlN/6H-SiC is significantly larger than that of individual materials, yet the relaxation time shows a opposite trend. This phenomenon can be attributed to the increased dipole moment within heterojunction interface, which is induced by the charge transfer due to the interface effect. This work advances the knowledge into high-temperature microwave-attenuating compounds and provides important theoretical guidance for designing high-efficient radio frequency and power electronic devices.