On The Electronic Contribution to Elastic Constants of Ultrathin Films of P-Type Si

1991 ◽  
Vol 226 ◽  
Author(s):  
Kamaxhya P Ghatak ◽  
Badal De
Keyword(s):  
Film Thickness ◽  
Experimental Method ◽  
Elastic Constants ◽  
Ultrathin Films ◽  
Hole Concentration ◽  
Electronic Contribution ◽  
Third Order ◽  
Theoretical Formulation ◽  
Third Order Elastic Constants ◽  
P Type

AbstractIn this paper we have formulated the electronic contribution to the elastic constants in ultrathin films of p-Si by considering the influences of heavy, light and split-off holes respectively. We have suggested an experimental method of determining the same in degenerate materials having arbitrary dispersion laws. The elastic constants increase with increasing hole concentration in an oscillatory way and decrease with increasing film thickness. The theoretical formulation is in agreement with the suggested experimental method of determining second and third order elastic constants.

Effect of Stress on the Carrier Contribution to Elastic Constants in Thin Films of Small Gap Compounds

1993 ◽  
Vol 308 ◽  
Author(s):  
Kamakhya P. Ghatak ◽  
Sambhu Nath Biswas
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Experimental Method ◽  
Elastic Constants ◽  
Electron Concentration ◽  
Ultrathin Films ◽  
Theoretical Formulation ◽  
Lattice Matched

ABSTRACTIn this paper we have investigated the carrier contribution to elastic constants in very thin films of stressed small gap compounds within the domain of theory. It is found, taking stressed ultrathin films Hg1-xCdxTe and In1-xGaxAsyP1-y lattice matched to InP as examples, that the elastic constants increase with increasing electron concentration and decreasing film thickness respectively in oscillatory manners. Besides the stress enhances the numerical values of such contribution to the elastic constants. In addition, the theoretical formulation is in agreement with the suggested experimental method of determining such constants in materials having arbitary dispersion laws.

The Electronic Contribution to The Elastic Constants of Strained III-V Materials Under High Magnetic Fields

1995 ◽  
Vol 379 ◽  
Author(s):  
Kamakhya P Ghatak ◽  
B. Nag ◽  
G. Mazumder
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Experimental Method ◽  
Elastic Constants ◽  
Quantitative Agreement ◽  
High Magnetic Fields ◽  
Electronic Contribution ◽  
Theoretical Formulation ◽  
Wide Gap ◽  
Lattice Matched

ABSTRACTIn this paper an attempt is made to study the electronic contribution to the elastic constants of strained III-V materials under high magnetic fields on the basis of k.p theory. It is found taking strained Hgi - x CdxTe and Ini - xGaxAsyPi-y lattice matched InP as examples that they increase with increasing doping and oscillate with inverse magnetic field respectively. The strain enhances the numerical values of the elastic constants. The theoretical formulation is in quantitative agreement with the suggested experimental method of determining the above contributions for degenerate materials having arbitrary dispersion laws. In addition, the well-known results for strain free wide gap materials in the absence of magnetic field have been obtained from our generalized analysis under certain limiting conditions.

Third Order Elastic Constants and Rayleigh Wave Dispersion of Shot Peened Aero-Engine Materials

2013 ◽  
Vol 768-769 ◽  
pp. 201-208 ◽  
Author(s):  
Marek Rjelka ◽  
Martin Barth ◽  
Sven Reinert ◽  
Bernd Koehler ◽  
Joachim Bamberg ◽  
...  
Keyword(s):  
Residual Stress ◽  
Rayleigh Wave ◽  
Elastic Constants ◽  
Cold Work ◽  
High Strength ◽  
Wave Dispersion ◽  
Third Order ◽  
Third Order Elastic Constants ◽  
Aero Engine ◽  
Rayleigh Wave Dispersion

Aero-engine components exposed to high mechanical stresses are made of high-strength alloys and additionally, they are surface treated by shot peening. This process introduces compressive residual stress into the material making it less sensitive to stress corrosion cracking and fatigue and therefore benefits the components performance and lifetime. Moreover cold work is induced in an amount depending on the peening parameters. To approximate the remaining lifetime, a quantitative, non-destructive method for stress assessment is required. It was shown that surface treatment of such alloys can be characterized by broadband Rayleigh wave dispersion measurements. However, the relative contributions of residual stress and cold work, respectively, remained an open point. This paper presents the determination of third order elastic constants (TOEC) for IN718 and Ti6246, providing, together with a model for the inversion of dispersion data, a quantitative access to the acoustoelastic effect. Finally, some measurements of differently treated samples are given.

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