Open FCC · Wide channels
FCC(310)
FCC(310) is a gentler tilt from (100) than (210), so its (100)-like terraces are wider. Straight rows bound elongated channels across the surface.
- Plane
- (310)
- Layer character
- Stepped · anisotropic
- ASE slab builder
surface
From bulk to facet
How FCC(310) is cut
(310)
The [310] normal is closer to [100] than [210] is. That smaller miscut produces wider (100)-like terraces before the next ledge.
- Bulk lattice
- Face-centred cubic
- Plane normal
- [310]
- What remains
- Wide channels
The plane is drawn through the centre so high-index cuts remain legible. Its orientation is what the indices specify, not its absolute position inside one cell.
Surface geometry
Read the surface from above
L1 is the highest atom-bearing plane, followed by L2 and L3. Support coordinates outside 0–1 are periodic images. The listed Δz describes the supporting atoms, not the marker height. In the interactive model, every numbered site is placed on the same schematic guide plane above the slab; no adsorption distance or energetic ordering is implied.
- terrace ontop1-fold
Above an atom within the (100)-like terrace.
(u,v) = (3/10, 0)s = s₁ · support shell: mean Δz = -0.571 Å from L1Projection of the L2 atom at (3/10, 0).
Not named in ASE - raised-row ontop1-fold
Above a low-coordinate atom on the raised row.
(u,v) = (3/20, 1/2)s = s₁ · support shell: mean Δz = +0.000 Å from L1Projection of the L1 atom at (3/20, 1/2).
Not named in ASE - row bridge2-fold
Between neighbours along the raised row.
(u,v) = (3/20, 0)s = (s₁ + s₂) / 2 · support shell: mean Δz = +0.000 Å from L1Periodic midpoint of L1 (3/20, 1/2) and L1 (3/20, 3/2).
Not named in ASE - terrace bridge2-fold
Between adjacent atoms within the terrace.
(u,v) = (3/10, 1/2)s = (s₁ + s₂) / 2 · support shell: mean Δz = -0.571 Å from L1Periodic midpoint of L2 (3/10, 0) and L2 (3/10, -1).
Not named in ASE - cross-row bridge2-fold
Between the raised row and a terrace atom.
(u,v) = (9/40, 1/4)s = (s₁ + s₂) / 2 · support shell: mean Δz = -0.285 Å from L1Periodic midpoint of L1 (3/20, 1/2) and L2 (3/10, 0).
Not named in ASE - terrace fourfold hollow4-fold
At a four-atom opening within the terrace.
(u,v) = (1/20, 1/2)s = (Σᵢ sᵢ) / 4 · support shell: mean Δz = -0.571 Å from L1Least-squares centroid of the 4-atom projected shell: L2 (3/10, 0), L2 (3/10, -1), L2 (-1/5, 0), L2 (-1/5, -1).
Not named in ASE - channel fourfold hollow4-fold
In the fourfold channel between rows.
(u,v) = (7/20, 1/2)s = (Σᵢ sᵢ) / 4 · support shell: mean Δz = -0.285 Å from L1Least-squares centroid of the 4-atom projected shell: L1 (3/20, 1/2), L1 (13/20, 1/2), L2 (3/10, 0), L2 (3/10, 1).
Not named in ASE - step pocket3-fold
A mixed-height pocket beside the raised row.
(u,v) = (3/10, 1/3)s = (Σᵢ sᵢ) / 3 · support shell: mean Δz = -0.571 Å from L1Least-squares centroid of the 3-atom projected shell: L1 (3/20, 3/2), L2 (3/10, 1), L3 (9/20, 3/2).
Not named in ASE
Interactive model
Rotate the slab
Sites share a schematic display height · drag to rotate · hover for names
Below the top layer
Why the sites are different
Comparing (210) and (310) shows how increasing the first index widens the terrace while retaining the same broad step direction.
Cell
Geometry at a glance
Here \(d_{310}=a/\sqrt{10}\), and the angle between [310] and [100] is \(\cos^{-1}(3/\sqrt{10})\approx18.4^\circ\).
A site name describes the ideal starting geometry. Relaxation can move an adsorbate away from it.
Practical model
Build it with ASE
The builder creates the slab. Sites marked ASE keyword can be passed directly as a named position; ASE source marks current but inconsistently documented support. Other sites require explicit Cartesian coordinates converted from the fractional construction above.
from ase.build import bulk, surface
cu = bulk("Cu", "fcc", a=3.61, cubic=True)
slab = surface(cu, (3, 1, 0), layers=8, vacuum=10)
Things that are easy to misread
- Interchanging the long and short in-plane directions.
- Using a square supercell notation for a fundamentally rectangular repeat.