Practical Electron Microscopy and Database

An Online Book, Second Edition by Dr. Yougui Liao (2006)

Practical Electron Microscopy and Database - An Online Book

Chapter/Index: Introduction | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Appendix

Surface Energies of Solids

The anisotropy of surface energies (γ) for metals (e.g. Cu in Table 2478) is normally less important than for oxides (e.g. CeO2 in Table 2478). In consequence, metal crystals can approximately be described by spheres and show a large number of different facets and rounded edges on their surface. Because the surface energy anisotropy of ionic crystals is very large they behave differently.

The surface energies of solids are difficult to measure. In many cases, the γ values are obtained by calculations with first principles. Table 2478 lists some surface energies of low-index surfaces.

Table 2478. Some surface energies (J/m2) of low-index surfaces. The types of reconstructions are indicated. (1x1) relaxed denotes an unreconstructed cleavage surface. Note the red numbers are only normalized values.

Solid
(100)
(110)
(111)
(311)
(511)
(522)
(531)
(210)
(211)
fcc
0.89
0.95
0.78
0.95
0.98
1.00
bcc
1.00
0.71
0.87
0.80

Si

1.41     c(4 × 4)

1.7     (1 × 1) relaxed

1.36    7 × 7
Si
2.13     at 77 K
1.51     at 77 K
1.23    at 77 K
1.56
Ge
1.0     c(4 × 4)
1.17     (1 × 1) relaxed
1.01    c(2 × 8)
GaAs
0.96     β2(2 × 4)
0.83     (1 × 1) relaxed
0.87    (2 x 2) Ga vacancy

 

InAs
0.75     β2(2 × 4)
0.66     (1 × 1) relaxed
0.67    (2 x 2) In vacancy
InP
0.99     β2(2 × 4)
0.88     (1 × 1) relaxed
0.99    (2 x 2) In vacancy
Au
1.60
1.28
0.80
Cu
1.62
1.66
1.55
1.82
1.68
CeO2
2.12
1.58
1.09