Low-index SC · Rectangular rows

SC(110)

SC(110) exposes a rectangular net whose short and long directions are inequivalent. The result has two distinct bridge orientations and an elongated fourfold opening.

Plane: (110)
Layer character: Flat · anisotropic
ASE slab builder: surface

From bulk to facet

How SC(110) is cut

(110) plane cutting through a Simple cubic bulk unit cell — The coloured sheet is one translated member of the (110) plane family; translating it along its normal gives an equivalent termination.

(110)

The plane meets two cubic axes equally and remains parallel to the third, producing rows along [001] separated along the face diagonal.

Bulk lattice: Simple cubic
Plane normal: [110]
What remains: Rectangular rows

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

surface second layer third layer

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.

Top view of SC(110) with numbered adsorption sites — The outlined reference cell has |a₁| = 4.7376 Å, |a₂| = 3.3500 Å, and γ = 90.00° for the Po slab used in the drawing. Fractional coordinates mean r_∥ = ua₁ + va₂.

ontop1-fold
Above an atom in the outermost rectangular row.
(u,v) = (1/2, 0)s = s₁ · support shell: mean Δz = +0.000 Å from L1
Projection of the L1 atom at (1/2, 0).
Not named in ASE
short bridge2-fold
Midpoint along the shorter c-axis surface repeat.
(u,v) = (1/2, 1/2)s = (s₁ + s₂) / 2 · support shell: mean Δz = +0.000 Å from L1
Periodic midpoint of L1 (1/2, 0) and L1 (1/2, 1).
Not named in ASE
long bridge2-fold
Midpoint between atoms across the longer in-plane repeat.
(u,v) = (0, 0)s = (s₁ + s₂) / 2 · support shell: mean Δz = +0.000 Å from L1
Periodic midpoint of L1 (1/2, 0) and L1 (3/2, 0).
Not named in ASE
rectangular hollow4-fold
Centre of the elongated rectangle formed by four surface atoms.
(u,v) = (0, 1/2)s = (Σᵢ sᵢ) / 4 · support shell: mean Δz = +0.000 Å from L1
Least-squares centroid of the 4-atom projected shell: L1 (1/2, 0), L1 (3/2, 0), L1 (1/2, 1), L1 (3/2, 1).
Not named in ASE

Interactive model

Rotate the slab

Sites share a schematic display height · drag to rotate · hover for names

Building the model…

Below the top layer

Why the sites are different

Consecutive atom-bearing planes shift by half the long surface repeat, making the lower rows visible between outermost rows in projection.

Side profile showing one compact stacking repeat. The dashed line follows the macroscopic surface plane.

Layer registry viewed from above; opacity increases towards the surface.

Cell

Geometry at a glance

The plane spacing is \(d_{110}=a/\sqrt{2}\). A rectangular surface cell has sides \(a\sqrt{2}\) and \(a\).

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

po = bulk("Po", "sc", a=3.35, cubic=True)
slab = surface(po, (1, 1, 0), 8, vacuum=10)

Things that are easy to misread

Treating the short and long bridge positions as symmetry equivalent.
Reading projected second-layer atoms as part of the outermost plane.