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 :
7 : module m_wann_dipole_electronic
8 : use m_juDFT
9 : contains
10 0 : subroutine wann_dipole_electronic(
11 0 : > natd,pos,omtil,
12 : > jspins,l_absolute,num_wann,
13 : < electronic_moment)
14 : c*********************************************
15 : c Calculate the dipole moment due to
16 : c Wannier-electrons.
17 : c
18 : c This subroutine can operate in two modes:
19 : c
20 : c i) l_absolute=.true. => Simply evaluate
21 : c the center of mass moment of all
22 : c Wannier functions.
23 : c
24 : c ii) l_absolute=.false. => Sum up the dipoles
25 : c that arise from the displacements of the
26 : c Wannier functions' centers from their
27 : c host atoms.
28 : c
29 : c Frank Freimuth
30 : c*********************************************
31 :
32 : USE m_constants
33 : use m_wann_readcenters
34 :
35 : implicit none
36 :
37 : integer, intent(in) :: natd
38 : real, intent(in) :: pos(3,natd)
39 : real, intent(in) :: omtil
40 : integer, intent(in) :: jspins
41 : logical, intent(in) :: l_absolute
42 : integer, intent(in) :: num_wann(2)
43 : real, intent(out) :: electronic_moment(3,2)
44 :
45 : real :: electronic_polarization(3,2)
46 : real,parameter :: elemchargmu=1.60217646e-13
47 : real,parameter :: bohrtocm=0.529177e-8
48 : integer :: jspin,j
49 : logical :: l_file
50 : character(len=2) :: spin12(0:2)
51 : character(len=6) :: filename
52 : integer :: num_wann_dum
53 0 : integer, allocatable :: waind(:)
54 : integer :: nwf,k
55 0 : real, allocatable :: wann_centers(:,:)
56 :
57 : data spin12/' ', '.1', '.2'/
58 :
59 0 : call timestart("wann_dipole_electronic")
60 0 : write(666,*)"*****************************"
61 0 : write(666,*)" Electronic terms "
62 0 : write(666,*)"*****************************"
63 0 : write(*,*) "*****************************"
64 0 : write(*,*) " Electronic terms "
65 0 : write(*,*) "*****************************"
66 :
67 0 : electronic_moment=0.0
68 :
69 0 : do jspin=1,jspins
70 0 : if(.not.l_absolute)then
71 : c--------reading the proj.1 / proj.2 / proj file
72 0 : do j=jspin,0,-1
73 0 : inquire(file=trim('proj'//spin12(j)),exist=l_file)
74 0 : if(l_file)then
75 0 : filename='proj'//spin12(j)
76 0 : exit
77 : endif
78 : enddo
79 :
80 0 : if(l_file)then
81 0 : open (203,file=trim(filename),status='old')
82 0 : rewind (203)
83 : else
84 : CALL juDFT_error("no proj/proj.1/proj.2",calledby
85 0 : + ="wann_dipole_electronic")
86 : endif
87 0 : read(203,*)num_wann_dum
88 0 : if(num_wann_dum/=num_wann(jspin)) CALL juDFT_error
89 0 : + ("num_wann_dum",calledby ="wann_dipole_electronic")
90 0 : allocate( waind(num_wann(jspin)) )
91 0 : do nwf=1,num_wann(jspin)
92 0 : read(203,*)waind(nwf)
93 0 : read(203,*)
94 : enddo
95 0 : close(203)
96 : endif
97 0 : print*,"number of wannier functions= ",num_wann(jspin)
98 0 : write(oUnit,*)"number of wannier functions",num_wann(jspin)
99 0 : allocate( wann_centers(3,num_wann(jspin)) )
100 : call wann_readcenters(
101 : > num_wann(jspin),jspin,
102 0 : < wann_centers(:,:))
103 0 : if(l_absolute)then
104 0 : do k=1,num_wann(jspin)
105 : electronic_moment(:,jspin)=
106 0 : & electronic_moment(:,jspin)-wann_centers(:,k)
107 : enddo
108 : else
109 0 : do k=1,num_wann(jspin)
110 : electronic_moment(:,jspin)=
111 : & electronic_moment(:,jspin)+
112 : + pos(:,waind(k))-
113 0 : - wann_centers(:,k)
114 : enddo
115 0 : deallocate(waind)
116 : endif
117 0 : deallocate(wann_centers)
118 0 : write(*, fmt=555)jspin,electronic_moment(:,jspin)
119 0 : write(666,fmt=555)jspin,electronic_moment(:,jspin)
120 0 : if(.not.l_absolute)then
121 : electronic_polarization=
122 0 : & electronic_moment/omtil*elemchargmu/((bohrtocm)**2)
123 0 : write(*, fmt=777)jspin,electronic_polarization(:,jspin)
124 0 : write(666,fmt=777)jspin,electronic_polarization(:,jspin)
125 : endif
126 : enddo
127 : 555 format("spin ",i1.1," electronic moment = (",3f12.6,") a.u.")
128 : 777 format("spin ",i1.1,
129 : & " electronic polarization = (",3f12.6,") uC/cm**2")
130 :
131 0 : call timestop("wann_dipole_electronic")
132 0 : end subroutine wann_dipole_electronic
133 : end module m_wann_dipole_electronic
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