Tuning the lattice thermal conductivity of bilayer penta-graphene by interlayer twisting

Abstract

Penta-graphene (PG) is the well-known prototype of the extensively studied 2D pentagon-based materials in recent years, and twisting strategy has been widely used to tune the properties of 2D sheets since the discovery of superconductivity in twisted bilayer graphene. However, no study is reported on how twisting affects the phonon properties of such penta-sheets. In this work, for the first time, we study the effect of twisting on the phonon transport properties of PG by using density functional theory and the phonon Boltzmann transport equation combined with two-channel transport theory and machine learning method. It is found that the in-plane lattice thermal conductivity of the twisted bilayer PG with a twist angle of 36.87° is only 96.72 W/mK at 300 K, reduced by 77.16% as compared to that of untwisted bilayer PG, and the four-phonon interaction further reduces the thermal conductivity by nearly 36%, while the coherence contribution to the thermal conductivity is enhanced to 9.69 W/mK from 0.13 W/mK by twisting. These results indicate that interlayer twisting not only can enhance three- and four-phonon scattering but also can uplift phonon coherence due to the resulted complex atomic configuration and high anharmonicity in bilayer PG.