Line data    Source code

       1              : !--------------------------------------------------------------------------------
       2              : ! Copyright (c) 2016 Peter Grünberg Institut, Forschungszentrum Jülich, Germany
       3              : ! This file is part of FLEUR and available as free software under the conditions
       4              : ! of the MIT license as expressed in the LICENSE file in more detail.
       5              : !--------------------------------------------------------------------------------
       6              : MODULE m_bfield
       7              :    USE m_juDFT
       8              : CONTAINS
       9          674 :   SUBROUTINE bfield(input,stars,noco,atoms,field,vTot,nococonv)
      10              :     !This subroutine adds a Zeeman-field to the potential
      11              :     !field%b_field is the field applied everywhere
      12              :     !field%b_field_mt is the field specific to the MT-sphere of a single atom type
      13              :     USE m_types
      14              :     USE m_constants
      15              :     USE m_rotMMPmat
      16              :     
      17              :     IMPLICIT NONE
      18              :     TYPE(t_input),INTENT(IN)::input
      19              :     TYPE(t_noco),INTENT(IN) ::noco
      20              :     TYPE(t_stars),INTENT(IN) :: stars
      21              :     TYPE(t_atoms),INTENT(IN)::atoms
      22              :     TYPE(t_field),INTENT(IN)::field
      23              :     TYPE(t_potden),INTENT(INOUT)::vtot
      24              :     TYPE(t_nococonv):: nococonv
      25              :     INTEGER :: iType
      26              :     COMPLEX :: bOffdiag
      27              :     REAL :: bExternal(4)
      28              : 
      29              :     
      30          674 :     IF (.NOT.field%l_b_field) RETURN !no B-field specified
      31              : 
      32            0 :     IF (input%jspins.NE.2) CALL judft_error("B-fields can only be used in spin-polarized calculations")
      33              :     !IF (noco%l_noco) CALL judft_error("B-fields not implemented in noco case")
      34              :     
      35              :     !Interstitial
      36            0 :     vTot%pw_w(:,1)=vTot%pw_w(:,1)-(field%b_field/2.0)*stars%ustep(:)
      37            0 :     vTot%pw_w(:,2)=vTot%pw_w(:,2)+(field%b_field/2.0)*stars%ustep(:)
      38              : 
      39              :     !MT-spheres
      40            0 :     DO iType = 1, atoms%ntype
      41            0 :        bExternal = 0.0
      42            0 :        bOffdiag = 0.0
      43            0 :        bExternal(1) = -field%b_field / 2
      44            0 :        bExternal(2) = field%b_field / 2
      45              : 
      46            0 :        IF (noco%l_noco) THEN
      47            0 :           CALL nococonv%rotdenmat(nococonv%alph(iType), nococonv%beta(iType), bExternal(1), bExternal(2), bOffdiag, .FALSE.)
      48            0 :           bExternal(3) = REAL(bOffdiag)
      49            0 :           bExternal(4) = AIMAG(bOffdiag)
      50              :        END IF
      51              : 
      52            0 :        vTot%mt(:atoms%jri(iType),0,iType,1) = vTot%mt(:atoms%jri(iType),0,iType,1) + sfp_const * (bExternal(1) * 2.0 - field%b_field_mt(iType)) / 2.0
      53            0 :        vTot%mt(:atoms%jri(iType),0,iType,2) = vTot%mt(:atoms%jri(iType),0,iType,2) + sfp_const * (bExternal(2) * 2.0 + field%b_field_mt(iType)) / 2.0
      54              : 
      55            0 :        IF (noco%l_noco) THEN
      56            0 :           vTot%mt(:atoms%jri(iType),0,iType,3) = vTot%mt(:atoms%jri(iType),0,iType,3) + sfp_const * bExternal(3)
      57            0 :           vTot%mt(:atoms%jri(iType),0,iType,4) = vTot%mt(:atoms%jri(iType),0,iType,4) + sfp_const * bExternal(4)
      58              :        END IF
      59              :     ENDDO
      60              : 
      61              :     !Vacuum
      62            0 :     IF (input%film) THEN
      63            0 :        vTot%vac(:,1,:,1)=vTot%vac(:,1,:,1)-field%b_field/2.0
      64            0 :        vTot%vac(:,1,:,2)=vTot%vac(:,1,:,2)+field%b_field/2.0
      65              :     END IF
      66              :   END SUBROUTINE bfield
      67              : END MODULE m_bfield