2016/10/03 by Jaeyun Moon, Moon, Jaeyun, Austin J. Minnich +1 · 1 citation
Materials Science · #FOS: Physical sciences #Graphene research and applications #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Silicon Nanostructures and Photoluminescence #Thermal properties of materials
paper · pdf · doi:10.48550/arxiv.1610.00810
openalex publication_date 2016/10/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Pure amorphous solids are traditionally considered to set the lower bound of\nthermal conductivity due to their disordered atomic structure that impedes\nvibrational energy transport. However, the lower limits for thermal\nconductivity in heterogeneous amorphous solids and the physical mechanisms\nunderlying these limits remain unclear. Here, we use equilibrium molecular\ndynamics to show that an amorphous SiGe nanocomposite can possess thermal\nconductivity substantially lower than those of the amorphous Si and Ge\nconstituents. Normal mode analysis indicates that the presence of the Ge\ninclusion localizes vibrational modes with frequency above the Ge cutoff in the\nSi host, drastically reducing their ability to transport heat. This observation\nsuggests a general route to achieve exceptionally low thermal conductivity in\nfully dense solids by restricting the vibrational density of states available\nfor transport in heterogeneous amorphous nanocomposites.\n