Structural property-induced different phonon-twin-boundary scattering in diamond

2021 ◽  
Vol 23 (6) ◽  
pp. 3874-3882
Author(s):  
Huicong Dong ◽  
Shuaichao Yu ◽  
Zhihao Feng ◽  
Bin Wen
Keyword(s):  
Twin Boundary ◽  
Structural Property ◽  
Boundary Energy ◽  
Boundary Scattering ◽  
Strongly Correlated

Twin boundary thermal resistances vary significantly with their structures, and they are strongly correlated with twin boundary energy and bond difference parameter.

DFT study of hydrogen and helium defects at the (112̄1) twin boundary in hcp scandium

2017 ◽  
Vol 31 (11) ◽  
pp. 1750080
Author(s):  
Kaimin Fan ◽  
Jing Tang ◽  
Li Yang ◽  
Yongqing Hu ◽  
Qingqiang Sun ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Twin Boundary ◽  
Density Functional ◽  
Nearest Neighbor ◽  
Boundary Energy ◽  
Boundary Plane ◽  
Octahedral Interstice ◽  
Tetrahedral Interstice ◽  
Densities Of States ◽  
Formation Energies

We have investigated the grain boundary energy of ([Formula: see text]) twin boundaries, the formation energies of hydrogen (H) and helium (He) defects in tetrahedral (T) and octahedral (O) interstitial sites at the ([Formula: see text]) twin boundary in hcp scandium (Sc) by first-principles calculations based on density functional theory. It is found that the formation energies of the tetrahedral and octahedral interstices H, and tetrahedral interstice He increase significantly towards the ([Formula: see text]) twin boundary plane, while the formation energy of the octahedral interstice He atom near the ([Formula: see text]) twin boundary plane decreases. To analyze these results, we present the electronic densities of states (DOSs) of H, He and their nearest-neighbor Sc (NN-Sc) atoms in several tetrahedral and octahedral configurations. We have also calculated the formation energies of He-vacancy clusters (He[Formula: see text]V) in the Sc grain boundary, which indicates the stabilities of He[Formula: see text]V clusters depend on the variations of the relaxed vacancy volume near the ([Formula: see text]) twin boundary plane.

Mechanical and Optical Properties Characterization of C-Plane (0001) and M-Plane (10−10) GaN by Nanoindentation and Luminescence

2015 ◽  
Vol 1792 ◽  
Author(s):  
Toshiya Yokogawa ◽  
Masaki Fujikane ◽  
Shijo Nagao ◽  
Roman Nowak
Keyword(s):  
Plastic Deformation ◽  
Shear Stress ◽  
Dislocation Density ◽  
Twin Boundary ◽  
Boundary Energy ◽  
Dynamics Simulation ◽  
Dark Spot ◽  
Yield Shear Stress ◽  
Gan Crystal

ABSTRACTYield shear stress dependence on dislocation density and crystal orientation was studied in bulk GaN crystals by nanoindentation examination. The yield shear stress decreased with increasing dislocation density which is estimated by dark spot density in cathodoluminescence, and it decreased with decreasing nanoindentation strain-rate. It reached and coincided at 11.5 GPa for both quasi-static deformed c-plane (0001) and m-plane (10-10) GaN. Taking into account theoretical Peierls–Nabarro stress and yield stress for each slip system, these phenomena were concluded to be an evidence of heterogeneous mechanism associated plastic deformation in GaN crystal. Transmission electron microscopy and molecular dynamics simulation also supported the mechanism with obtained r-plane (-1012) slip line right after plastic deformation, so called pop-in event. The agreement of the experimentally obtained atomic shuffle energy with the calculated twin boundary energy suggested that the nucleation of the local metastable twin boundary along the r-plane concentrated the indentation stress, leading to an r-plane slip. This nanoindentation examination is useful for the characterization of crystalline quality because the wafer mapping of the yield shear stress coincided the photoluminescence mapping which shows increase of emission efficiency due to reduction of non-radiative recombination process by dislocation.

Enormous suppression of phonon transport in silicon nanowires with five-fold twin boundary

2018 ◽  
Vol 6 (38) ◽  
pp. 18533-18542 ◽  
Author(s):  
Yufei Gao ◽  
Yanguang Zhou ◽  
Ming Hu
Keyword(s):  
Twin Boundary ◽  
Silicon Nanowires ◽  
Phonon Transport ◽  
Boundary Scattering

The five-fold twin boundary not only leads to much more intense boundary scattering, but also results in vibrational hybridization.

scholarly journals High density of genuine growth twins in electrodeposited aluminum

2019 ◽  
Vol 5 (10) ◽  
pp. eaax3894 ◽  
Author(s):  
Lidija D. Rafailović ◽  
Christoph Gammer ◽  
Christian Ebner ◽  
Christian Rentenberger ◽  
Aleksandar Z. Jovanović ◽  
...  
Keyword(s):  
Twin Boundary ◽  
Boundary Energy ◽  
Synthesis Method ◽  
High Density ◽  
Adsorbed Hydrogen ◽  
Structure And Properties ◽  
Dft Methods ◽  
Viable Approach ◽  
Very High

We demonstrate electrodeposition as a synthesis method for fabrication of Al coatings, up to 10 μm thick, containing a high density of genuine growth twins. This has not been expected since the twin boundary energy of pure Al is very high. TEM methods were used to analyze deposited Al and its nanoscaled twins. DFT methods confirmed that the influence of the substrate is limited to the layers close to the interface. Our findings are different from those achieved by sputtering of Al coatings restricted to a thickness less than 100 nm with twins dominated by epitaxial effects. We propose that in the case of electrodeposition, a high density of twins arises because of fast nucleation and is additionally promoted by a monolayer of adsorbed hydrogen originating from water impurities. Therefore, electrodeposition is a viable approach for tailoring the structure and properties of thicker, deposited Al coatings reinforced by twins.

Theoretical Study of Twin Boundary Structure and Twin Boundary Energy of Mo-Re Alloy

1993 ◽  
Vol 126-128 ◽  
pp. 113-116
Author(s):  
Takeshi Shinoda ◽  
Kinichi Masuda-Jindo ◽  
Shin Takeuchi ◽  
Yoshinao Mishima ◽  
T. Suzuki
Keyword(s):  
Twin Boundary ◽  
Theoretical Study ◽  
Boundary Energy ◽  
Boundary Structure

Effects of Si and Al on twin boundary energy of TiC

2003 ◽  
Vol 51 (9) ◽  
pp. 2477-2484 ◽  
Author(s):  
R Yu ◽  
L.L He ◽  
H.Q Ye
Keyword(s):  
Twin Boundary ◽  
Boundary Energy

Twin boundary energy of hierarchically twinned magnetic shape memory alloys

2011 ◽  
Vol 99 (9) ◽  
pp. 092512 ◽  
Author(s):  
Anett Diestel ◽  
Anja Backen ◽  
Ulrich K. Rößler ◽  
Ludwig Schultz ◽  
Sebastian Fähler
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Twin Boundary ◽  
Boundary Energy ◽  
Magnetic Shape Memory ◽  
Magnetic Shape Memory Alloys
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