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yambo-code / yambo

This is the official GPL repository of the yambo code
http://www.yambo-code.eu/
GNU General Public License v2.0
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QP correction applied only to few bands lead to non physical occupations #60

Open sangallidavide opened 11 months ago

sangallidavide commented 11 months ago

For example applying a stretching to bulk iron of test-suite when doing a BSE calculation with bands from 5 to 10 leads to the following energies and occupations.

 [QP_apply] Action to be applied: USER defined scissor

  [04.01]  QP corrections report
  ==============================

  [K+QP] === General ===
  [K+QP] Electronic Temperature                     :  0.258693E-1   300.200    [eV K]
  [K+QP] Bosonic    Temperature                     :  0.258606E-1   300.100    [eV K]
  [K+QP] Finite Temperature mode                    : yes
  [K+QP] El. density                                :  0.67814E+24 [cm-3]
  [K+QP] Fermi Level                                : -3.170129 [eV]

  [K+QP] === Gaps and Widths ===
  [K+QP] Conduction Band Min                        : -3.170129 [eV]
  [K+QP] Valence Band Max                           : -3.170129 [eV]
  [K+QP] Filled Bands                               :  10
  [K+QP] Empty Bands                                :   5  20

  [K+QP] === Metallic Characters ===
  [K+QP] N of el / N of met el                      :  8.000000  0.000000
  [K+QP] Average metallic occ.                      :  0.000000

  [WARNING] [K+QP] Metallic system

  Eqp @ K [ 1]
   -4.18075  -4.05053   0.92893   0.98412 -22.08835 -21.47579 -19.64319 -17.36086
  -17.23808 -16.29019   4.43012   5.39058  25.54383  25.61119  27.15088  27.25378
  Eqp @ K [ 2]
   -1.44541  -0.45291   0.36015   0.58579 -20.55967 -19.19084 -19.08801 -17.88579
  -16.45774 -14.01948   5.45836   5.95674  14.05958  15.07340  21.47403  22.11517
  Eqp @ K [ 3]
   -2.15004  -1.88616   0.15134   0.15255 -20.22450 -20.11913 -19.70416 -19.67519
  -17.50186 -12.55490   5.11368   5.40319  20.05680  20.10777  20.50891  20.56504
sangallidavide commented 11 months ago

Fix code with commit 131555e in my fork. To be merged in the main repo. After the fix the energy order is correct, although the position of Fermi level, VBM and CBM is off

  [04.01]  QP corrections report
  ==============================

  [K+QP] === General ===
  [K+QP] Electronic Temperature                     :  0.258693E-1   300.200    [eV K]
  [K+QP] Bosonic    Temperature                     :  0.258606E-1   300.100    [eV K]
  [K+QP] Finite Temperature mode                    : yes
  [K+QP] El. density                                :  0.67814E+24 [cm-3]
  [K+QP] Fermi Level                                : -20.49898 [eV]

  [K+QP] === Gaps and Widths ===
  [K+QP] Conduction Band Min                        : -20.49898 [eV]
  [K+QP] Valence Band Max                           : -20.49898 [eV]
  [K+QP] Filled Bands                               :   7
  [K+QP] Metallic Bands                             :   8   9
  [K+QP] Empty Bands                                :  10  20

  [K+QP] === Metallic Characters ===
  [K+QP] N of el / N of met el                      :  8.000000  0.854852
  [K+QP] Average metallic occ.                      :  0.213713

  [WARNING] [K+QP] Metallic system

  Eqp @ K [ 1]
  -10.21015 -10.07993  -5.10046  -5.04527  -4.75949  -4.14693  -2.31433  -0.03201
    0.09078   1.03866   1.87962   2.84008  22.99333  23.06069  24.60038  24.70328
  Eqp @ K [ 2]
  -6.557595 -5.565097 -4.752039 -4.526397 -3.230813 -1.861981 -1.759159 -0.556933
    0.87112   3.30937   4.27029   4.76867  12.87150  13.88533  20.28596  20.92709
  Eqp @ K [ 3]
  -7.061131 -6.797250 -4.759746 -4.758533 -2.895648 -2.790272 -2.375306 -2.346337
   -0.17301   4.77395   4.80435   5.09386  19.74747  19.79844  20.19958  20.25571