Understanding lattice dynamics is crucial for effective thermal management in electronic devices. This paper investigates the phonon dynamics of α-GaN, a crucial third-generation power semiconductor, using inelastic X-ray and neutron scattering, along with first-principles calculations. A Matryoshka phonon dispersion is revealed, amplifying phonon anharmonicity and reducing in-plane thermal transport due to increased three-phonon scattering. This contributes to α-GaN's anisotropic thermal conductivity and offers insights into phonon topology engineering for thermal management in semiconductors.

Bin Wei, Qingan Cai, Qiyang Sun, Yaokun Su, Ayman H. Said, Douglas L. Abernathy, Jiawang Hong, Chen Li