Realization of Phonon FETs in 2D material through Engineered Acoustic Mismatch

Field-effect transistors (FETs) predominantly utilize electrons for signal processing in modern electronics. In contrast, phonon-based field-effect transistors (PFETs)-which employ phonons for active thermal management-remain markedly underdeveloped, with effectively reversible thermal conductivity modulation posing a significant challenge. Herein, we propose a novel PFET architecture enabling reversible thermal conductivity modulation. This design integrates a substrate in the central region with a two-dimensional (2D) material to form an engineered junction, exploiting differences in out-of-plane acoustic phonon properties to regulate heat flow. Molecular dynamics simulations of a graphene (Gr)/hexagonal boron nitride (h-BN) junction demonstrate a substantial thermal conductivity reduction up to 44-fold at 100 K. The effect is maintained at room temperature and across diverse substrates, confirming robustness. This work establishes a new strategy for dynamic thermal management in electronics.