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Thermal conductivity of silicon nanowires: From fundamentals to phononic engineering

  1. Top of page
  2. Thermal conductivity of silicon nanowires: From fundamentals to phononic engineering
  3. Silicene on hydrogen-passivated Si(111) and Ge(111) substrate
  4. Atomistic origin of rapid crystallization of Ag-doped Ge–Sb-Te alloys: a joint experimental and theoretical study

Gang Zhang and Yong-Wei Zhang

The thermal conductivity of silicon nanowires can be altered by introducing different phonon scattering mechanisms. These scat-tering mechanisms manifest themselves as the dominant ones only in a certain range of frequency regimes. The study to control and modify the phonon thermal conductivity of nanowires via manipulating their internal structure, composition and defects is referred by the authors as “phononic engineering”. Phononic engineering will provide an efficient and practically useful tool for controlling the thermal conductivity of nanomaterials.

Phys. Status Solidi RRL (2013) DOI 10.1002∕pssr.201307188.

pssa201370044-gra-0001

Silicene on hydrogen-passivated Si(111) and Ge(111) substrate

  1. Top of page
  2. Thermal conductivity of silicon nanowires: From fundamentals to phononic engineering
  3. Silicene on hydrogen-passivated Si(111) and Ge(111) substrate
  4. Atomistic origin of rapid crystallization of Ag-doped Ge–Sb-Te alloys: a joint experimental and theoretical study

Sebastian Kokott, Lars Matthes, and Friedhelm Bechstedt

The growth of silicene, the graphene-like allotrope of silicon, is an unsolved challenge. As a favorable approach the silicene formation on a hydrogenated Si(111) or Ge(111) substrate is predicted. Its stability and electronic properties are demonstrated by first-principles studies. The weak van-der-Waals interaction between silicene and substrates does not destroy its linear bands forming Dirac cones at the Brillouin zone corners. Only very small fundamental gaps are opened around the Fermi level.

Phys. Status Solidi RRL (2013) DOI 10.1002∕pssr.201307215.

pssa201370044-gra-0002

Atomistic origin of rapid crystallization of Ag-doped Ge–Sb-Te alloys: a joint experimental and theoretical study

  1. Top of page
  2. Thermal conductivity of silicon nanowires: From fundamentals to phononic engineering
  3. Silicene on hydrogen-passivated Si(111) and Ge(111) substrate
  4. Atomistic origin of rapid crystallization of Ag-doped Ge–Sb-Te alloys: a joint experimental and theoretical study

B. Prasai, M. E. Kordesch, D. A. Drabold, and G. Chen

Experimental and theoretical studies of Ag–doped Ge1Sb2Te4 have revealed that the average Ge–Te bond length increases with Ag concentration, whereas the Sb–Te and Ag–Te bond lengths remain unchanged. The increase in the fraction of distorted octahedral Ge sites ex–plains the net increase in Ge–Te bond lengths, and appears to be responsible for the faster crystallization of Ge–Sb–Te alloys caused by doping as confirmed by molecular dynamics simula–tions. Furthermore, the high fraction of Ag–Te suggests that Ag prefers bonding with Te to Ge and Sb. This study sheds light on the atomistic mechanism of rapid crystallization of GST alloys enhanced by Ag doping.

Phys. Status Solidi B (2013) DOI 10.1002∕pssb.201349150.

pssa201370044-gra-0003