Diamond has a measured Peierls stress of about

PHYSICS · Subjective · Fermi University Physics · Fluids & Continuum Physics · Condensed Matter, Materials & Soft Matter · Crystal structure, bonding and diffraction

Solid State Physics, Ch Point defects, dislocations and alloys

Problem

Diamond has a measured Peierls stress of about τP≈0.1G\tau_P\approx0.1G, with Poisson ratio ν≈0.2\nu\approx0.2. Using τP≈2G1−νe−2πw/b,\tau_P\approx\frac{2G}{1-\nu}e^{-2\pi w/b}, estimate the dislocation core width ww, in units of the Burgers vector bb, implied by this value. Compare it with silicon's core width of about w≈bw\approx b (implied by silicon's τP≈10−2G\tau_P\approx10^{-2}G), and comment on the trend from silicon to diamond in terms of bond directionality.

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