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density.f90
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210 lines (172 loc) · 7.67 KB
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module dens
implicit none
! Parameters for spinorb = .true. case
complex*16, save, public, allocatable :: init_denssoc(:,:,:,:,:), dens_matsoc(:,:,:,:,:)
real*8 , save, public, allocatable :: init_magsoc(:,:)
! Parameters for spinorb = .false. case
complex*16, save, public, allocatable :: init_dens(:,:,:,:), dens_mat(:,:,:,:)
real*8 , save, public, allocatable :: init_mag(:)
real*8 , save, public :: efermi, num
public :: initialize_density_matrix
public :: set_fermi_level
public :: set_density_matrix_soc
public :: set_density_matrix
contains
subroutine initialize_density_matrix()
use param, only : nelec, ntot, nsite, norb, sigma_x, sigma_y, sigma_z, spinorb
use constants, only : nspin, elecname, cmplx_0, cmplx_i
implicit none
logical :: io_find
integer :: i, isite, ispin1, iorb, ispin, neps
integer , allocatable :: nup(:), ndown(:)
if (.not. spinorb) then
allocate(init_mag(nsite))
inquire(file=elecname, exist=io_find)
if (io_find) then
open(2, file=elecname, status='old')
do isite = 1, nsite
read(2,*) init_mag(isite)
end do
close(2)
end if
else if (spinorb) then
allocate(init_magsoc(3,nsite))
inquire(file=elecname, exist=io_find)
if (io_find) then
open(2, file=elecname, status='old')
do isite = 1, nsite
read(2,*) init_magsoc(:,isite)
end do
close(2)
end if
end if
neps = nelec/nsite
if (.not.spinorb) then
allocate(init_dens(norb,norb,nsite,nspin))
allocate(dens_mat(norb,norb,nsite,nspin))
! Initialize collinear spins, this is only provisional
init_dens = cmplx_0
do isite = 1, nsite
do iorb = 1, norb
do ispin = 1, nspin
init_dens(iorb,iorb,isite,ispin) = real(neps)/(2.0*real(norb))
end do
end do
do ispin = 1, nspin
init_dens(:,:,isite,ispin) = init_dens(:,:,isite,ispin) + &
& + init_mag(isite)*sigma_z(:,:,ispin,ispin)/(2.0*real(norb))
end do
end do
else if (spinorb) then
allocate(init_denssoc(norb,norb,nsite,nspin,nspin))
allocate(dens_matsoc(norb,norb,nsite,nspin,nspin))
! Initialize collinear spins, this is only provisional
init_denssoc = cmplx_0
do isite = 1, nsite
do iorb = 1, norb
do ispin = 1, nspin
init_denssoc(iorb,iorb,isite,ispin,ispin) = real(neps)/(2.0*real(norb))
end do
end do
do iorb = 1, norb
init_denssoc(iorb,iorb,isite,1,1) = init_denssoc(iorb,iorb,isite,1,1) + init_magsoc(3,isite)/(2.0*real(norb))
init_denssoc(iorb,iorb,isite,2,2) = init_denssoc(iorb,iorb,isite,2,2) - init_magsoc(3,isite)/(2.0*real(norb))
init_denssoc(iorb,iorb,isite,1,2) = init_denssoc(iorb,iorb,isite,1,2) + (init_magsoc(1,isite) + &
cmplx_i*init_magsoc(2,isite))/(2.0*real(norb))
init_denssoc(iorb,iorb,isite,2,1) = init_denssoc(iorb,iorb,isite,2,1) + (init_magsoc(1,isite) - &
cmplx_i*init_magsoc(2,isite))/(2.0*real(norb))
end do
end do
end if
end subroutine initialize_density_matrix
subroutine set_fermi_level(eigenval,beta)
use param, only : nkpt, ntot, nener, nkpt, nelec
use utilities, only : heavyside, fermi_dirac
real*8 , intent(in) :: eigenval(ntot,nkpt), beta
real*8 :: emax, emin, emax_tmp, emin_tmp, e, etmp, numax, numin
integer :: ikpt, itot, i
emax = maxval(eigenval(ntot,:))
emin = minval(eigenval(1,:))
numax = 0.0
numin = 0.0
do itot = 1, ntot
do ikpt = 1, nkpt
numax = numax + fermi_dirac((eigenval(itot,ikpt)-emax),beta)/real(nkpt)
numin = numin + fermi_dirac((eigenval(itot,ikpt)-emin),beta)/real(nkpt)
end do
end do
if ((numax > nelec) .and. (numin < nelec)) then
do i = 1, 30
num = 0
e = (emax-emin)/2.0 + emin
do itot = 1, ntot
do ikpt = 1, nkpt
num = num + fermi_dirac((eigenval(itot,ikpt)-e),beta)/real(nkpt)
end do
end do
if (abs(num-nelec) < 1e-6) then
efermi = e
exit
else if (num < nelec) then
emin = e
else if (num > nelec) then
emax = e
end if
end do
end if
end subroutine set_fermi_level
subroutine set_density_matrix(eigenvec,eigenval,beta)
use param, only : nkpt, ntot, norb, nsite
use constants, only : nspin, cmplx_0
use utilities, only : fermi_dirac
integer :: ikpt, itot, iorb, iorb1, ispin, ispin1, isite
complex*16, intent(in) :: eigenvec(norb*nsite,norb*nsite,nspin,nkpt)
real*8, intent(in) :: eigenval(norb*nsite,nspin,nkpt), beta
dens_mat = cmplx_0
do itot = 1, norb*nsite
do ikpt = 1, nkpt
do isite = 1, nsite
do iorb = 1, norb
do iorb1 = 1, norb
dens_mat(iorb,iorb1,isite,1) = dens_mat(iorb,iorb1,isite,1) + &
& + fermi_dirac((eigenval(itot,1,ikpt)-efermi),beta)* &
conjg(eigenvec((isite-1)*norb+iorb,itot,1,ikpt))* &
eigenvec((isite-1)*norb+iorb1,itot,1,ikpt)/real(nkpt)
dens_mat(iorb,iorb1,isite,2) = dens_mat(iorb,iorb1,isite,2) + &
& + fermi_dirac((eigenval(itot,2,ikpt)-efermi),beta)* &
conjg(eigenvec((isite-1)*norb+iorb,itot,2,ikpt))* &
eigenvec((isite-1)*norb+iorb1,itot,2,ikpt)/real(nkpt)
end do
end do
end do
end do
end do
end subroutine set_density_matrix
subroutine set_density_matrix_soc(eigenvec,eigenval,beta)
use param, only : nkpt, ntot, norb, nsite
use constants, only : nspin, cmplx_0
use utilities, only : fermi_dirac
integer :: ikpt, itot, iorb, iorb1, ispin, ispin1, isite
complex*16, intent(in) :: eigenvec(ntot,ntot,nkpt)
real*8, intent(in) :: eigenval(ntot,nkpt), beta
dens_matsoc = cmplx_0
do itot = 1, ntot
do ikpt = 1, nkpt
do isite = 1, nsite
do ispin = 1, nspin
do ispin1 = 1, nspin
do iorb = 1, norb
do iorb1 = 1, norb
dens_matsoc(iorb,iorb1,isite,ispin,ispin1) = dens_matsoc(iorb,iorb1,isite,ispin,ispin1) + &
& + fermi_dirac((eigenval(itot,ikpt)-efermi),beta) * &
conjg(eigenvec((isite-1)*norb+iorb+(ispin-1)*norb*nsite,itot,ikpt))* &
eigenvec((isite-1)*norb+iorb1+(ispin1-1)*norb*nsite,itot,ikpt)/nkpt
end do
end do
end do
end do
end do
end do
end do
end subroutine set_density_matrix_soc
end module dens