Large Suppression of Phonon Thermal Transport in F‑Diamane under Biaxial Tensile Strain

Strain engineering is one of the most effective ways to regulate materials’ properties, and it can regulate phonon thermal transport by inducing changes in lattice vibrations. In this study, we have systematically investigated the effect of biaxial tensile strain on the lattice thermal conductivity (κ) of surface-fluorinated diamane (F-diamane) by first-principles calculations combined with phonon Boltzmann transport theory. Despite only slight lattice changes, a biaxial tensile strain of 6% results in a reduced κ to 40% of that without strain at room temperature. Specifically, strain results in softening of phonon modes, especially optical phonons, which contribute significantly to κ. Moreover, bond weakening due to strain enhances phonon anharmonicity. The enhanced phonon scattering rate leads to a substantial reduction in the phonon lifetime. This work offers critical insights into structure and energy transport properties in a novel family of two-dimensional carbon-based materials.