Dynamic Control of Heterointerface Coupling in Magnetic van der Waals Heterostructures via Pressure Engineering.

Heterointerface coupling provides a versatile platform for investigating emergent quantum phenomena and enabling high-performance devices. Although numerous strategies have been developed to tune this coupling, the dynamics of heterointerface coupling and its cooperative interplay with external pressure remain poorly understood. Here, we demonstrate dynamic control of interlayer coupling by pressure engineering in a heterostructure comprising monolayer WSe2 and the room-temperature ferromagnet Fe3GaTe2. Pressure-dependent photoluminescence spectroscopy reveals an abnormal excitonic energy-shift transition and the emergence of a pressure-induced low-energy feature in WSe2 at elevated pressures, both of which are strongly modulated by heterointerface coupling. First-principles calculations attribute the shift transition to a pressure-driven change in the dominant radiative pathway from K-K to K-Q transitions, whereas the low-energy feature arises from a phonon sideband enabled by enhanced electron-phonon coupling under pressure. The strengthened interlayer coupling accelerates the direct-to-indirect excitonic crossover and amplifies electron-phonon interactions, explaining the advanced exciton-shift transition and the appearance of phonon sidebands in the heterostructure. These findings establish a synergistic route for multistage modulation of excitonic and vibronic responses in van der Waals systems, offering a practical framework for pressure-enabled heterointerface engineering toward high-performance quantum and optoelectronic devices.