Structural evolution of amorphous SiO2 and its impact on interfacial heat transport with β-Ga2O3

• A DFT-accurate Deep Potential model for SiO 2 is developed and validated for large-scale molecular dynamics simulations. • The structural evolution of amorphous SiO 2 is systematically studied over a wide range of quenching rates (1–100 K/ps). • Slower quenching enhances medium-range ordering and density, leading to a ∼40 % increase in thermal conductivity. • Interfacial thermal conductance in β-Ga 2 O 3 /a-SiO 2 heterostructures exhibits strong dependence on SiO 2 quenching rate and substrate orientation. • Enhanced vibrational spectral overlap between β-Ga 2 O 3 and slowly quenched SiO 2 facilitates more efficient interfacial phonon transmission. Amorphous silica (a‑SiO 2 ) serves as an essential dielectric and structural material in microelectronics, photonics, and advanced power devices. Its thermal and structural properties are strongly governed by variations in atomic topology, which are in turn highly sensitive to fabrication processing such as melt‑quench cooling. In this study, we employ a machine‑learning interatomic potential with DFT accuracy to systematically investigate the amorphization of SiO 2 over a wide range of quenching rates and to examine the implications of amorphous topology on thermal transport. Molecular dynamics simulations reveal that rapid quenching produces a highly disordered network with broad distributions of local defects, whereas slow quenching enables enhanced medium‑range ordering and densification. These structural differences lead to pronounced variations in thermal conductivity. Extending the analysis to β‑Ga 2 O 3 /a‑SiO 2 heterointerfaces, we show that the interfacial thermal conductance is strongly influenced by the vibrational spectrum of a‑SiO 2 and its quench‑rate‑dependent relaxation. This work establishes an atomistic link between amorphous topology, vibrational features, and interfacial heat transport, offering guidance for designing thermally efficient oxide heterostructures.