Examining normal modes as fundamental heat carriers in amorphous solids: The case of amorphous silicon

Normal mode decomposition of atomic vibrations has been used to provide microscopic under-standing thermal transport in amorphous solids for decades. In normal methods, it is naturally assumed that atoms vibrate around their equilibrium positions and individual modes are the fundamental vibrational excitations transporting heat. With abundance predictions from methods experimental measurements now available, we care-fully analyze these calculations silicon, a model solid. We find number discrepancies, suggesting treating as heat carriers may not be accurate solids. Further, our classical ab-initio molecular dynamics simulations silicon demonstrate large degree diffusion, especially at high temperatures, leading conclusion could better described starting perspective liquid rather than crystalline