
979
The Physics of
5.2. The Physics of Solid Surfaces
The data compiled in this chapter refer to so-called
“clean surfaces”, i. e. crystalline surfaces that are
atomically clean and well characterized. Data
on interfaces are dealt with only marginally, in
connection with MOS devices.
The values reported in the tables are mainly
averages from several different authors. In such
cases the errors are given as standard deviations.
Reference to the individual measurements and to
the original papers is made by referring to larger
compilations (mainly the four volumes of Landolt–
Börnstein III/24, Physics of Solid Surfaces,[2.1]or
the single articles therein [2.2–16]). On the other
hand, the figures are fully referenced.
5.2.1 The Structure of Ideal Surfaces............. 979
5.2.1.1 Diagrams of Surfaces [2.2] ........ 979
5.2.1.2 Crystallographic Formulas......... 986
5.2.2 Surface Reconstruction and Relaxation. 986
5.2.2.1 Definitions and Notation.......... 986
5.2.2.2 Metals ................................... 987
5.2.2.3 Semiconductors ...................... 987
5.2.3 Electronic Structure of Surfaces ............ 996
5.2.3.1 Metals ................................... 997
5.2.3.2 Semiconductors ...................... 1003
5.2.3.3 Magnetic Surfaces ................... 1007
5.2.4 Surface Phonons................................. 1012
5.2.4.1 Metals ................................... 1012
5.2.4.2 Semiconductors
and Insulators ........................ 1017
5.2.4.3 Atom–Surface Potential ........... 1019
5.2.5 The Space Charge Layer at the Surface
of a Semiconductor............................. 1020
5.2.5.1 Definitions and Notation.......... 1020
5.2.5.2 Useful Formulas
and Numerical Values .............. 1022
5.2.5.3 Surface Conductivity ................ 1023
5.2.6 Most Frequently Used Acronyms ........... 1026
References ..................................................1029
5.2.1 The Structure of Ideal Surfaces
An ideal surface is a surface of a half-crystal in which
the atoms are held in their original positions. The struc-
ture of an ideal surface is identical to that of a parallel
crystallographic plane in the bulk. For a 2-D lattice, the
elementary Bravais cell can have only one of the five
structures shown in Fig. 5.2-1.
5.2.1.1 Diagrams of Surfaces [2.2]
Figure 5.2-2 gives diagrams of ideal surfaces for some
common faces of the fcc (face-centered cubic), bcc
(body-centered cubic), diamond, and zinc blende sys-
tems, as well as the coordinates of the atoms of the
first layers of the half-crystal. The atoms are drawn as
solid balls with diameters appropriate to close-packed
stacking.
Atoms in the surface layer are labeled by O, A, B,
C, ... . Atoms in the first, second, third, etc. sublayer
are labeled by 1, 2, 3, ... . When two classes of atoms
are present (for example in diamond-like structures),
the atoms of the second class are indicated by primed
symbols. In such a case, the division of an ideal crys-
tal by a geometrical plane may expose different types
of surfaces. A well-known example is the (111) face
of NaCl-type crystals, which may be either anion- or
cation-terminated.
Part 5 2