Phonon computations
This is a quick sketch how to run a simple phonon calculation using DFTK.
Practical phonon computations have only seen rudimentary testing as of now. As of now we do not yet recommend relying on this feature for production calculations. We appreciate any issues, bug reports or PRs.
First we run an SCF calculation.
using AtomsBuilder
using DFTK
using PseudoPotentialData
pseudopotentials = PseudoFamily("cp2k.nc.sr.lda.v0_1.semicore.gth")
model = model_DFT(bulk(:Si); pseudopotentials, functionals=LDA())
basis = PlaneWaveBasis(model; Ecut=10, kgrid=[4, 4, 4])
scfres = self_consistent_field(basis, tol=1e-8);n Energy log10(ΔE) log10(Δρ) Diag Δtime
--- --------------- --------- --------- ---- ------
1 -7.916441077308 -0.69 4.8 110ms
2 -7.921207220624 -2.32 -1.52 1.0 55.3ms
3 -7.921406110344 -3.70 -2.49 1.4 59.4ms
4 -7.921440993798 -4.46 -2.83 2.5 89.0ms
5 -7.921441671012 -6.17 -3.04 1.1 57.0ms
6 -7.921442008524 -6.47 -4.55 1.1 57.5ms
7 -7.921442021908 -7.87 -4.67 2.9 85.2ms
8 -7.921442022133 -9.65 -5.32 1.0 56.1ms
9 -7.921442022142 -11.04 -5.60 1.6 62.5ms
10 -7.921442022144 -11.65 -6.02 1.0 56.1ms
11 -7.921442022144 -12.60 -6.79 1.0 69.0ms
12 -7.921442022144 -13.40 -7.28 2.4 73.1ms
13 -7.921442022144 + -Inf -7.77 1.4 63.3ms
14 -7.921442022144 + -15.05 -8.24 1.4 63.1msNext we compute the phonon modes at the q-point [1/4, 1/4, 1/4].
scfres = DFTK.unfold_bz(scfres)
phret_q0 = @time DFTK.phonon_modes(scfres; q=[0.25, 0.25, 0.25]);Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.1 3.72s Non-interacting
1 0 1 0.31 52.7 3.94s
2 0 2 -0.52 47.2 1.59s
3 0 3 -2.40 42.0 1.43s
4 0 4 -4.46 30.0 1.11s
5 0 5 -6.46 17.6 800ms
6 0 6 -8.91 4.0 442ms
7 1 1 -7.87 55.6 2.18s Restart
8 1 2 -9.08 5.5 489ms
72.9 2.12s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.1 1.97s Non-interacting
1 0 1 0.31 52.7 1.82s
2 0 2 -0.52 47.2 1.57s
3 0 3 -2.40 42.0 1.43s
4 0 4 -4.46 30.0 1.11s
5 0 5 -6.46 17.6 794ms
6 0 6 -8.91 4.0 446ms
7 1 1 -7.87 55.6 2.14s Restart
8 1 2 -9.08 5.5 475ms
72.9 2.14s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.1 1.96s Non-interacting
1 0 1 0.31 52.7 1.82s
2 0 2 -0.52 47.2 1.54s
3 0 3 -2.40 42.0 1.42s
4 0 4 -4.46 30.0 1.11s
5 0 5 -6.46 17.6 798ms
6 0 6 -8.91 4.0 436ms
7 1 1 -7.87 55.6 2.12s Restart
8 1 2 -9.08 5.5 479ms
72.9 2.10s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.1 1.94s Non-interacting
1 0 1 0.31 52.7 1.80s
2 0 2 -0.52 47.2 1.55s
3 0 3 -2.40 42.0 2.66s
4 0 4 -4.46 30.0 1.19s
5 0 5 -6.46 17.5 775ms
6 0 6 -8.91 4.0 409ms
7 1 1 -7.85 55.9 2.09s Restart
8 1 2 -9.09 5.6 477ms
72.9 2.09s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.1 1.94s Non-interacting
1 0 1 0.31 52.7 1.79s
2 0 2 -0.52 47.2 1.54s
3 0 3 -2.40 42.0 1.42s
4 0 4 -4.46 30.0 1.10s
5 0 5 -6.46 17.5 780ms
6 0 6 -8.91 4.0 443ms
7 1 1 -7.85 55.9 2.10s Restart
8 1 2 -9.09 5.6 476ms
72.9 2.07s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.1 1.93s Non-interacting
1 0 1 0.31 52.7 1.77s
2 0 2 -0.52 47.2 1.54s
3 0 3 -2.40 42.0 1.42s
4 0 4 -4.46 30.0 1.10s
5 0 5 -6.46 17.5 780ms
6 0 6 -8.91 4.0 425ms
7 1 1 -7.85 55.9 2.08s Restart
8 1 2 -9.09 5.6 467ms
72.9 2.07s Final orbitals
98.851981 seconds (101.48 M allocations: 80.492 GiB, 8.04% gc time, 7.34% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.0034981553607239956
-0.002977451160935513
-0.0029774511602397536
0.004302230621450548
0.00430223062192956
0.004353201752852598