Synergistic competition mechanism of phonon scattering in uniaxial (100) strain diamond: A first-principles study

The miniaturization of high-frequency electronic devices has led to heat accumulation in their components. The ultrahigh thermal conductivity of diamond makes it an ideal material for heat dissipation, but factors such as temperature changes during the working process, special structures, thermal stress, and lattice mismatch can affect performance. This study investigated the effects of stress, temperature, isotope purity, and feature size on the thermal conductivity of diamond using a first-principles method. The sensitivity to size effects of the thermal conductivity of uniaxially strained diamond differed according to the scale. Under a low temperature (100 K), and with a feature size of 1 µm, the thermal conductivity of diamond with large-scale tensile strain exceeded that of a diamond with small-scale strain, which was an anomalous phenomenon. Isotope purification did not significantly affect the variation rule of the thermal conductivity of strained diamond.