Abstract: High-pressure has been widely utilized to improve material performances such as thermal conductivity κ and interfacial thermal conductance G. Gallium arsenide (GaAs) as a functional semiconductor has attracted extensive attention in high-pressure studies for its technological importance and complex structure transitions. Thermal properties of GaAs under high pressure are urgent needs in physics but remain elusive. Herein, we systematically investigate κ_GaAs and G_Al/GaAs of multi-structure up to ∼23 GPa. We conclude that: (1) in pressurization, phonon group velocity, lattice defects, and electrons play a central role in κ_GaAs in elastic, plastic, and metallization regions, respectively. The increased phonon density of states (PDOS) overlap, group velocity, and interfacial bonding enhances G_Al/GaAs. (2) In depressurization, electrons remain the dominant factor on κ_GaAs from 23 to 13.5 GPa. G_Al/GaAs increases dramatically at ∼12 GPa due to the larger PDOS overlap. With decompressing to ambient, lattice defects including grain size reduction, arsenic vacancies, and partial amorphization reduce κ_GaAs to a glass-like value. Remarkably, the released G_Al/GaAs is 2.6 times higher than that of the initial. Thus our findings open a new dimension in synergistically realizing glass-like κ and enhancing G, which can facilitate thermoelectric performance and its potential engineering applications.

Key words: Gallium arsenide, High pressure, Thermal conductivity, Interfacial thermal conductance, Time domain thermoreflectance