Strain effect on the phonon transport properties of hydrogenated 2D GaN

Abstract

Surface hydrogenation on 2D GaN has received extensive attention since surface passivation broadens its application in electronic devices. Strain is inevitably introduced in the process of 2D material synthesis, and its effects on thermal transport need to be discussed. In this work, we performed a detailed study on the strain-dependent thermal transport properties of hydrogenated monolayer GaN (H-GaN). With the increasing of strain, the thermal conductivity of H-GaN rises first and then descends, showing a volcanic shape. Detailed analyses show that the primary factor affecting the trend origins from the change of phonon lifetime. Fundamental understanding of the lifetime trend is achieved by electronic structures. It is found that due to the competition between the polarity and strength of Ga-N bond, atom vibration anharmonicity first drops and then enhances with the increasing of strain. Moreover, mean free path shows that strain combined nanostructure engineering could regulate the thermal transport properties effectively due to size effect.