Bi2Se3
Bi2Se3 is a 3D strongly topological insulator.
Here we don't list the standard procedure to construct Wannier functions with Wannier90, please read VASP wiki or user guide of Wannier90.
In this example, we choose VASP to do the first principle calculation and construct Wannier functions. We only list the key input files.
Bi2Se3
1.0
-2.069 -3.583614 0.000000
2.069 -3.583614 0.000000
0.000 2.389075 9.546667
Bi Se
2 3
Direct
0.3990 0.3990 0.6970
0.6010 0.6010 0.3030
0 0 0.5
0.2060 0.2060 0.1180
0.7940 0.7940 0.8820
SYSTEM = Bi2Se3
EDIFF = 1E-8
PREC = N
LSORBIT = .TRUE.
LORBIT = 11
ISMEAR = 0
SIGMA = 0.05
GGA = PE
ISYM = -1
ENCUT = 300.00 eV
MAGMOM = 3600*0.0
ISTART = 1
ICHARG = 11
NBANDS = 60
LWANNIER90 = .TRUE.
LWRITE_MMN_AMN = .TRUE.
num_wann = 30
num_bands = 60
num_iter=0
dis_num_iter=1000
dis_win_min = -2.0
dis_win_max = 18.0
dis_froz_min = -2.0000
dis_froz_max = 5.5000
hr_plot =.true.
begin projections
Bi : px; py; pz
Se : px; py; pz
end projections
spinors = .true.
When we get wannier90_hr.dat and input.dat, put them into the same folder, then
run in single processor
wann_tools >log &
run in multi-core system
mpiexec -np 4 wann_tools >log &
or
mpirun -np 4 wann_tools >log &
&TB_FILE
Hrfile = wannier90_hr.dat
/
&CONTROL
!> bulk band structure calculation flag
BulkBand_calc = T
BulkFS_calc = F
BulkGap_cube_calc = F
BulkGap_plane_calc = F
SlabBand_calc = T
WireBand_calc = F
SlabSS_calc = T
SlabArc_calc = T
SlabSpintexture_calc = T
wanniercenter_calc = F
BerryPhase_calc = F
BerryCurvature_calc = F
/
&SYSTEM
NSLAB = 10
NumOccupied = 18 ! NumOccupied
SOC = 1 ! soc
E_FERMI = 4.4195 ! e-fermi
Bx= 0, By= 0, Bz= 0 ! Bx By Bz
surf_onsite= 0.0 ! surf_onsite
/
&PARAMETERS
Eta_Arc = 0.001 ! infinite small value, like brodening
E_arc = 0.0 ! energy for calculate Fermi Arc
OmegaNum = 500 ! omega number
OmegaMin = -0.6 ! energy interval
OmegaMax = 0.5 ! energy interval
Nk1 = 100 ! number k points
Nk2 = 100 ! number k points
Nk3 = 20 ! number k points
NP = 2 ! number of principle layers
Gap_threshold = 1.0 ! threshold for GapCube output
/
LATTICE
Angstrom
-2.069 -3.583614 0.000000 ! crystal lattice information
2.069 -3.583614 0.000000
0.000 2.389075 9.546667
ATOM_POSITIONS
5 ! number of atoms for projectors
Direct ! Direct or Cartisen coordinate
Bi 0.3990 0.3990 0.6970
Bi 0.6010 0.6010 0.3030
Se 0 0 0.5
Se 0.2060 0.2060 0.1180
Se 0.7940 0.7940 0.8820
PROJECTORS
3 3 3 3 3 ! number of projectors
Bi px py pz ! projectors
Bi px py pz
Se px py pz
Se px py pz
Se px py pz
SURFACE ! See doc for details
1 0 0
0 1 0
0 0 1
KPATH_BULK ! k point path
4 ! number of k line only for bulk band
G 0.00000 0.00000 0.0000 Z 0.00000 0.00000 0.5000
Z 0.00000 0.00000 0.5000 F 0.50000 0.50000 0.0000
F 0.50000 0.50000 0.0000 G 0.00000 0.00000 0.0000
G 0.00000 0.00000 0.0000 L 0.50000 0.00000 0.0000
KPATH_SLAB
2 ! numker of k line for 2D case
K 0.33 0.67 G 0.0 0.0 ! k path for 2D case
G 0.0 0.0 M 0.5 0.5
KPLANE_SLAB
-0.1 -0.1 ! Original point for 2D k plane
0.2 0.0 ! The first vector to define 2D k plane
0.0 0.2 ! The second vector to define 2D k plane for arc plots
KPLANE_BULK
-0.50 -0.50 0.00 ! Original point for 3D k plane
1.00 0.00 0.00 ! The first vector to define 3d k space plane
0.00 1.00 0.00 ! The second vector to define 3d k space plane
KCUBE_BULK
-0.50 -0.50 -0.50 ! Original point for 3D k plane
1.00 0.00 0.00 ! The first vector to define 3d k space plane
0.00 1.00 0.00 ! The second vector to define 3d k space plane
0.00 0.00 1.00 ! The third vector to define 3d k cube
- Bulk band structure
set
BulkBand_calc = T
- Surface state spectrum A(k, E)
set
SlabSS_calc = T
You can increase the number of k points and number of energies to get high resolution pictures.
- Surface state spectrum A(k, E=E0)
set
SlabArc_calc = T
- Wannier charge center (WCC) at six k planes
For Bi2Se3, it is a strong topological insulator. So the topological index should be 1,(000), which means the z2 number for k=0 plane should be 1, and for k=0.5 plane should be 0.
please set this block to fix the plane you want to calculate the WCC
Wanniercenter_calc = T
KPLANE_BULK
0.00 0.00 0.00 ! Original point for 3D k plane
0.00 1.00 0.00 ! The first vector to define 3d k space plane
0.00 0.00 0.50 ! The second vector to define 3d k space plane
k3= 0.0
KPLANE_BULK
0.00 0.00 0.00 ! Original point for 3D k plane
1.00 0.00 0.00 ! The first vector to define 3d k space plane
0.00 0.50 0.00 ! The second vector to define 3d k space plane
k3= 0.5
KPLANE_BULK
0.00 0.00 0.50 ! Original point for 3D k plane
1.00 0.00 0.00 ! The first vector to define 3d k space plane
0.00 0.50 0.00 ! The second vector to define 3d k space plane
k2= 0.0
KPLANE_BULK
0.00 0.00 0.00 ! Original point for 3D k plane
1.00 0.00 0.00 ! The first vector to define 3d k space plane
0.00 0.00 0.50 ! The second vector to define 3d k space plane
k2= 0.5
KPLANE_BULK
0.00 0.50 0.00 ! Original point for 3D k plane
1.00 0.00 0.00 ! The first vector to define 3d k space plane
0.00 0.00 0.50 ! The second vector to define 3d k space plane
k1= 0.0
KPLANE_BULK
0.00 0.00 0.00 ! Original point for 3D k plane
0.00 1.00 0.00 ! The first vector to define 3d k space plane
0.00 0.00 0.50 ! The second vector to define 3d k space plane
k1= 0.5
KPLANE_BULK
0.50 0.00 0.00 ! Original point for 3D k plane
0.00 1.00 0.00 ! The first vector to define 3d k space plane
0.00 0.00 0.50 ! The second vector to define 3d k space plane
