Silicon Slab Structural Relaxation

Diamond

Single Layer

PBEsol

Pair Distribution Functions

a_PBEsol = 5.495 Å ; r_{NN, bulk, PBEsol} = 2.379 Å

Step	Displacement q (b1, b2, b3)	Build-in Factor	Total Energy (eV/atom)	Total Force (eV/Å/atom)	Cell Pressure (GPa)	Resulting Mean ω1 (cm-1)	Lowest ω (cm-1)
0	-	-	-90.40389544	6.90e-05	0.010	-0.493665	-63.177
1	9 (-0.526 0.254 0.000)	1.0	-90.33443035	4.50e-05	0.000	-0.718166	-59.031
2	3 (-0.001 -0.513 0.000)	1.0	-90.40389384	6.00e-05	-0.000	-0.597389	-64.901
3	9 (-0.510 0.223 0.000)	1.0	-90.39834846	4.50e-05	-0.010	0.839677	-13.822794
4	9 (-0.477 0.352 0.000)	1.0	-90.37901909	5.20e-05	-0.010	-0.181455	-42.396192
5	10 (-0.492 -0.709 0.000)	1.0	-90.47275885	4.10e-05	-0.050	-0.615533	-91.254540
6	10 (-0.610 -0.836 0.000)	1.0

Step	PDF
0
1
2
3
4
5

Phonon Bands and Density of States

Step	Phonons
0
1
2
3
4
5
6

Relaxation Procedure

1. Create slab using copies of bulk structure coordinates
2. Relax slab using loose total force convergence (~10^-3 Ry bohr)
3. Vary celldm(1) by fixed perentage around loosely relaxed slab and relax each new structure to tighter total force convergence (~10^-4 Ry bohr)
4. Relax the minimum-energy structure from that step to the tightest force convergence (~10^-5 Ry bohr)
5. Vary celldm(3) around the relaxed minimum energy structure and relax the in-plane (x & y) coordinates only
6. Fit the equation of state to these energies and volumes