[Pw_forum] Forces in full LDA+U scheme are not yet implemented

[Izaak Williamson]

Hello everyone,



I am using the DFT+U approach to compare my system with experimental results. To do so, I want to optimize the effective on-site Coulomb value (U) and keep the exchange value (J) fixed while simultaneously relaxing the structure using vc-relax. When I try and submit the vc-relax (or even relax) calculations, I get the following error:

 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     Error in routine force_hub (1):
      forces in full LDA+U scheme are not yet implemented
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

This doesn't seem right to me. Is it true what the error says, that the force calculations are not yet implemented in the "rotationally invariant scheme of Liechtenstein et. Al., using Hubbard_U and Hubbard_J"? Perhaps I have made a mistake in my input file. The system portion of my input file is given:

&SYSTEM
    ibrav            = 0
    celldm(1)        = 1.889725989
    nat              = 73
    ntyp             = 4
    ecutwfc          = 60
    ecutrho          = 600
    occupations      = 'smearing'
    degauss          = 0.001
    nspin            = 2
    starting_magnetization(1) = 0.5
    starting_magnetization(2) =-0.5
    tot_magnetization= 0.0
    lda_plus_u       = .t.
    lda_plus_u_kind  = 1
    Hubbard_U(1)     = 2.6
    Hubbard_U(2)     = 2.6
    Hubbard_J0(1)    = 1.2
    Hubbard_J0(2)    = 1.2
/

NOTE: Whenever lda_plus_u_kind is set to 1, any relax calculation gives the above error. When it is 0, it runs fine.

Is it necessary to include "lda_plus_u_kind = 1" parameter or will the code still incorporate U and J if I set it to 0 (simplified version of Cococcioni and de Gironcoli using Hubbard_U)?

Thanks in advance.

--
Izaak Williamson
Graduate Student
Department of Materials Science and Engineering
Boise State University
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20130227/36567208/attachment.html>