High-pressure Studies on Boron-containing Ultra-High Thermal Conductivity Material

Ultra-high thermal conductivity materials are of great scientific interest for thermal management applications. Boron arsenide (BAs) was predicted theoretically to have ultra-high thermal conductivity. Later it was experimentally discovered to have thermal conductivity exceeding 1000 W/mK at ambient conditions. Interestingly, theoretical calculations suggested that high pressure can be used to tune the thermal conductivity of BAs. Polytypes of BAs were predicted to occur at high pressure. However, there are not many high-pressure studies on BAs. Earlier high-pressure XRD studies on BAs observed pressure-induced amorphization at 125 GPa persistent up to 165 GPa. Recent high-pressure studies on BAs show the anomaly in pressure-dependent thermal conductivity. We have conducted high-pressure X-ray diffraction studies on BAs to understand structural stability and amorphization and to explore high-pressure polytypes using laser-heated diamond cells. Pressure- and temperature-dependent Raman studies have also been carried out on BAs to understand the phonon behavior and anharmonicity.