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 -7.916446916728 -0.69 4.8 101ms
2 -7.921208108816 -2.32 -1.52 1.0 57.6ms
3 -7.921407099179 -3.70 -2.49 1.2 55.1ms
4 -7.921440896390 -4.47 -2.83 2.6 72.7ms
5 -7.921441676517 -6.11 -3.05 1.1 53.9ms
6 -7.921442008256 -6.48 -4.52 1.1 59.2ms
7 -7.921442021879 -7.87 -4.66 2.9 79.6ms
8 -7.921442022136 -9.59 -5.34 1.1 54.3ms
9 -7.921442022142 -11.25 -5.61 1.4 57.4ms
10 -7.921442022144 -11.63 -6.15 1.0 59.2ms
11 -7.921442022144 -12.67 -6.71 1.6 60.5ms
12 -7.921442022144 -13.62 -7.64 1.9 64.3ms
13 -7.921442022144 -14.75 -7.87 2.1 71.3ms
14 -7.921442022144 -14.75 -8.97 1.0 60.1msNext 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 1.98s Non-interacting
1 0 1 0.31 52.8 2.22s
2 0 2 -0.52 47.2 1.47s
3 0 3 -2.40 41.9 1.33s
4 0 4 -4.46 30.0 1.04s
5 0 5 -6.46 17.5 735ms
6 0 6 -8.92 4.0 416ms
7 1 1 -7.83 55.9 2.00s Restart
8 1 2 -9.04 5.5 454ms
72.9 1.99s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.86s Non-interacting
1 0 1 0.31 52.8 1.73s
2 0 2 -0.52 47.2 1.53s
3 0 3 -2.40 41.9 1.36s
4 0 4 -4.46 30.0 1.06s
5 0 5 -6.46 17.5 747ms
6 0 6 -8.92 4.0 419ms
7 1 1 -7.83 55.9 2.02s Restart
8 1 2 -9.04 5.5 449ms
72.9 2.00s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.85s Non-interacting
1 0 1 0.31 52.8 2.59s
2 0 2 -0.52 47.2 1.47s
3 0 3 -2.40 41.9 1.34s
4 0 4 -4.46 30.0 1.05s
5 0 5 -6.46 17.5 751ms
6 0 6 -8.92 4.0 411ms
7 1 1 -7.83 55.9 2.00s Restart
8 1 2 -9.04 5.5 450ms
72.8 1.96s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.1 1.83s Non-interacting
1 0 1 0.31 52.8 1.70s
2 0 2 -0.52 47.2 1.47s
3 0 3 -2.40 41.9 1.34s
4 0 4 -4.46 29.9 1.06s
5 0 5 -6.46 17.5 737ms
6 0 6 -8.92 4.0 443ms
7 1 1 -7.86 55.8 1.99s Restart
8 1 2 -9.01 5.5 444ms
72.8 1.97s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.80s Non-interacting
1 0 1 0.31 52.8 1.68s
2 0 2 -0.52 47.2 1.45s
3 0 3 -2.40 41.9 2.10s
4 0 4 -4.46 29.9 1.04s
5 0 5 -6.46 17.5 748ms
6 0 6 -8.92 4.0 416ms
7 1 1 -7.86 55.8 1.99s Restart
8 1 2 -9.01 5.5 447ms
72.9 1.96s Final orbitals
Iter Restart Krydim log10(res) avg(CG) Δtime Comment
---- ------- ------ ---------- ------- ------ ---------------
73.0 1.82s Non-interacting
1 0 1 0.31 52.8 1.70s
2 0 2 -0.52 47.2 1.46s
3 0 3 -2.40 41.9 1.33s
4 0 4 -4.46 29.9 1.03s
5 0 5 -6.46 17.5 726ms
6 0 6 -8.92 4.0 408ms
7 1 1 -7.86 55.8 2.00s Restart
8 1 2 -9.01 5.5 451ms
72.8 1.95s Final orbitals
88.008628 seconds (92.54 M allocations: 80.118 GiB, 7.41% gc time, 1.21% compilation time: 100% of which was recompilation)These are the final phonon frequencies:
phret_q0.frequencies6-element Vector{Float64}:
-0.0034981553586376987
-0.002977451159967826
-0.0029774511598599264
0.004302230630658052
0.004302230630775612
0.0043532017611905135