3.2 Surface Reconstruction
69
(1x1)
(1x1)
(1x2)
(hex)
(a) Au (100)
(b) Au (110)
(c) Au (111)
Side view
( 3 x 22) : Surface atom layer
(1x1) : Underlying atom layer
Fig. 3.1 Structures of unreconstructed and reconstructed gold single-crystal surfaces [2]. a Au
(100): (1 × 1)↔(hex), b Au (110): (1 × 1)↔(1 × 2), and c Au (111): (1 × 1)↔(
√
3 × 22).
Reprinted from [2], Copyright 1996, with permission from Elsevier
layer which reduces the surface energy due to the decrease in electronic charge that
does not participate in bonding.
In the case of the (111) surface, the (111) surface of Pt does not spontaneously
reconstruct at temperature lower than 1330 K [6], while the Au (111) surface reconstructs into a
√
3 × 22
structure in which every 23rd surface atom is in register
with every 22nd atom of the underlying lattice, involving uniaxial compression by
about 4% in the surface layer along the [110] direction [1, 2]. The net change in
surface structure due to reconstruction is relatively small as compared to the (100)
and (110) surfaces since the unreconstructed (111) surface has the already densely
packed structure. As shown in Fig. 3.1c, the
√
3 × 22
surface has a complicated
structure in which the position of surface atoms with respect to the second layer
changes periodically between two different domains of fcc sites and hcp sites through
a domain wall of bridge sites [7].
In interfacial electrochemistry, it is known that the transition between reconstructed and unreconstructed surfaces for single-crystal electrodes such as Au and Pt
takes place, depending on applied potential and adsorption of electrolyte anions [1,
69
(1x1)
(1x1)
(1x2)
(hex)
(a) Au (100)
(b) Au (110)
(c) Au (111)
Side view
( 3 x 22) : Surface atom layer
(1x1) : Underlying atom layer
Fig. 3.1 Structures of unreconstructed and reconstructed gold single-crystal surfaces [2]. a Au
(100): (1 × 1)↔(hex), b Au (110): (1 × 1)↔(1 × 2), and c Au (111): (1 × 1)↔(
√
3 × 22).
Reprinted from [2], Copyright 1996, with permission from Elsevier
layer which reduces the surface energy due to the decrease in electronic charge that
does not participate in bonding.
In the case of the (111) surface, the (111) surface of Pt does not spontaneously
reconstruct at temperature lower than 1330 K [6], while the Au (111) surface reconstructs into a
√
3 × 22
structure in which every 23rd surface atom is in register
with every 22nd atom of the underlying lattice, involving uniaxial compression by
about 4% in the surface layer along the [110] direction [1, 2]. The net change in
surface structure due to reconstruction is relatively small as compared to the (100)
and (110) surfaces since the unreconstructed (111) surface has the already densely
packed structure. As shown in Fig. 3.1c, the
√
3 × 22
surface has a complicated
structure in which the position of surface atoms with respect to the second layer
changes periodically between two different domains of fcc sites and hcp sites through
a domain wall of bridge sites [7].
In interfacial electrochemistry, it is known that the transition between reconstructed and unreconstructed surfaces for single-crystal electrodes such as Au and Pt
takes place, depending on applied potential and adsorption of electrolyte anions [1,