▎ 摘　　要

Attributed to hyperbolic phonon polaritons (HPPs) of ferroelectric materials such as lithium tantalate (LiTaO3) and lithium niobate (LiNbO3) in low-THz frequencies (<20 THz), the ferroelectric/graphene heterostructure systems are put forward to obtain actively tunable hybrid plasmon-phonon polariton modes. When graphene layers are added in ferroelectric-based heterostructures, tunable hybrid plasmon-phonon polariton modes are obtained by the hybridization of fermelectric phonon polaritons and graphene plasmons, and these characteristics also lead to dramatic regulation of spontaneous emission (SE) rates. Moreover, SE rates in fermelectric/graphene heterostructure systems greatly rely on the ferroelectric thickness, graphene chemical potential and the emitter distance from the hetemstmcture. This work provides a meaningful instruction for actively tunable hybrid plasmon-phonon polariton modes and SE rate regulation in low-THz frequencies.