Phonon computations

This is a quick sketch how to run a simple phonon calculation using DFTK. 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   -7.916451015284                   -0.69    4.6    102ms
  2   -7.921209048588       -2.32       -1.52    1.0   53.0ms
  3   -7.921404562874       -3.71       -2.49    1.4   56.6ms
  4   -7.921440858483       -4.44       -2.82    2.5   72.3ms
  5   -7.921441575559       -6.14       -2.97    1.1   54.3ms
  6   -7.921442005334       -6.37       -4.49    1.0   61.4ms
  7   -7.921442021493       -7.79       -4.46    2.8   81.4ms
  8   -7.921442022117       -9.20       -5.19    1.0   55.0ms
  9   -7.921442022142      -10.60       -5.52    1.5   59.9ms
 10   -7.921442022143      -11.85       -5.96    1.2   57.7ms
 11   -7.921442022144      -12.22       -6.81    1.1   62.4ms
 12   -7.921442022144      -13.32       -7.14    2.4   72.3ms
 13   -7.921442022144      -14.75       -7.41    1.1   56.5ms
 14   -7.921442022144   +    -Inf       -8.04    1.0    104ms

Next 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
----  -------  ------  ----------  -------  ------  ---------------
                                      73.0   1.95s  Non-interacting
   1        0       1        0.31     52.4   2.22s
   2        0       2       -0.52     46.9   1.47s
   3        0       3       -2.40     41.7   1.35s
   4        0       4       -4.46     29.7   1.05s
   5        0       5       -6.46     17.5   741ms
   6        0       6       -8.91      4.0   1.11s
   7        1       1       -7.83     55.6   1.94s  Restart
   8        1       2       -8.87      5.6   458ms
                                      72.7   2.01s  Final orbitals
Iter  Restart  Krydim  log10(res)  avg(CG)  Δtime   Comment
----  -------  ------  ----------  -------  ------  ---------------
                                      73.0   1.84s  Non-interacting
   1        0       1        0.31     52.4   1.72s
   2        0       2       -0.52     46.9   1.48s
   3        0       3       -2.40     41.7   1.35s
   4        0       4       -4.46     29.7   1.05s
   5        0       5       -6.46     17.5   743ms
   6        0       6       -8.91      4.0   418ms
   7        1       1       -7.83     55.6   2.00s  Restart
   8        1       2       -8.87      5.6   460ms
                                      72.8   1.98s  Final orbitals
Iter  Restart  Krydim  log10(res)  avg(CG)  Δtime   Comment
----  -------  ------  ----------  -------  ------  ---------------
                                      73.0   1.83s  Non-interacting
   1        0       1        0.31     52.4   1.70s
   2        0       2       -0.52     46.9   1.45s
   3        0       3       -2.40     41.7   1.34s
   4        0       4       -4.46     29.7   1.04s
   5        0       5       -6.46     17.5   741ms
   6        0       6       -8.91      4.0   415ms
   7        1       1       -7.83     55.6   2.61s  Restart
   8        1       2       -8.87      5.6   447ms
                                      72.7   1.99s  Final orbitals
Iter  Restart  Krydim  log10(res)  avg(CG)  Δtime   Comment
----  -------  ------  ----------  -------  ------  ---------------
                                      73.0   1.86s  Non-interacting
   1        0       1        0.31     52.4   1.71s
   2        0       2       -0.52     46.9   1.47s
   3        0       3       -2.40     41.7   1.35s
   4        0       4       -4.46     29.7   1.06s
   5        0       5       -6.46     17.5   758ms
   6        0       6       -8.91      4.0   425ms
   7        1       1       -7.83     55.6   2.01s  Restart
   8        1       2       -8.87      5.6   459ms
                                      72.8   2.01s  Final orbitals
Iter  Restart  Krydim  log10(res)  avg(CG)  Δtime   Comment
----  -------  ------  ----------  -------  ------  ---------------
                                      72.9   1.85s  Non-interacting
   1        0       1        0.31     52.4   1.71s
   2        0       2       -0.52     46.9   1.48s
   3        0       3       -2.40     41.7   1.34s
   4        0       4       -4.46     29.7   1.04s
   5        0       5       -6.46     17.5   747ms
   6        0       6       -8.91      4.0   419ms
   7        1       1       -7.83     55.6   2.68s  Restart
   8        1       2       -8.87      5.6   420ms
                                      72.7   1.93s  Final orbitals
Iter  Restart  Krydim  log10(res)  avg(CG)  Δtime   Comment
----  -------  ------  ----------  -------  ------  ---------------
                                      72.9   1.85s  Non-interacting
   1        0       1        0.31     52.4   1.71s
   2        0       2       -0.52     46.9   1.48s
   3        0       3       -2.40     41.7   1.35s
   4        0       4       -4.46     29.7   1.05s
   5        0       5       -6.46     17.5   756ms
   6        0       6       -8.91      4.0   431ms
   7        1       1       -7.83     55.6   2.02s  Restart
   8        1       2       -8.87      5.6   459ms
                                      72.8   2.00s  Final orbitals
 88.193332 seconds (94.34 M allocations: 80.346 GiB, 7.28% gc time, 1.20% compilation time: 100% of which was recompilation)

These are the final phonon frequencies:

phret_q0.frequencies

6-element Vector{Float64}:
 -0.003498155362058426
 -0.0029774511597638674
 -0.002977451159257137
  0.004302230608897933
  0.004302230609497188
  0.004353201739721985