Generation of interfacial phonon modes and their contribution to thermal transport across the GaN/ZnO interface
Shuyue Shan, Zhongwei Zhang, Shuang Lü, Sebastian Volz, Jie Chen
Abstract
Interfacial phonon modes are pivotal to thermal transport across interfaces and are essential for optimizing heat dissipation in micro- and nanoscale devices. In this work, we investigate the generation mechanism of interfacial phonon modes and their contribution to thermal transport across the GaN/ZnO interface using atomic simulations. Our results identify two distinct types of interfacial phonon modes: additional emerging modes and enhanced pristine bulk modes, which are distributed on each side of the interface. By using an extended wavelet transform approach, we demonstrate that phonon polarization possesses a pronounced alignment with the orientation of covalent bonds at the interface, which elucidates their origin in coupled atomic vibrations extending across the interface. As a result, we find that only the longitudinal interfacial phonon modes are present near the GaN/ZnO interface with zigzag edges. Furthermore, we reveal that these unique characteristics enable the interfacial phonon modes to significantly enhance interfacial thermal conductance through a dual mechanism that simultaneously opens inelastic scattering channels and reinforces elastic ones. This study provides a fundamental understanding of interfacial thermal transport and phonon physics at the microscopic level, which might offer valuable insight to advanced thermal management in device applications.