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kSpin Error: No Bands are Found
Date: 2021/06/09 18:12
Name: Simba   <pshubham2805@gmail.com>

Dear Developers,

I am trying to calculate spin-texture for my system. I compiled the post-processing code kSpin successfully.

I did a normal scf calculation with following input tags in System.dat file with the Bands.Dispersion tag on and got the band structure:

scf.XcType GGA-PBE # LDA|LSDA-CA|LSDA-PW|GGA-PBE
scf.SpinPolarization nc # On|Off|NC
scf.partialCoreCorrection on # On|Off
scf.SpinOrbit.Coupling on # On|Off, default=off
scf.Constraint.NC.Spin Off # on|off, default=off
scf.Constraint.NC.Spin.v 1.0 # default=0.0(eV)
scf.ElectronicTemperature 300.0 # default=300 (K)
scf.energycutoff 150.0 # default=150 (Ry)
scf.maxIter 300 # default=40
scf.EigenvalueSolver Band # DC|GDC|Cluster|Band
scf.Kgrid 13 13 1 # means 4x4x4
scf.Mixing.Type Rmm-Diisk # Simple|Rmm-Diis|Rmm-Diisk
scf.Init.Mixing.Weight 0.1 # default=0.30
scf.Min.Mixing.Weight 0.001 # default=0.001
scf.Max.Mixing.Weight 0.4 # default=0.40
scf.Mixing.History 5 # default=5
scf.Mixing.StartPulay 6 # default=6
scf.criterion 1.0e-7 # default=1.0e-6 (Hartree)

1DFFT.NumGridK 900 # default=900
1DFFT.NumGridR 900 # default=900
1DFFT.EnergyCutoff 3600.0 # default=3600 (Ry)

#
# Orbital Optimization
#

orbitalOpt.Method off # Off|Unrestricted|Restricted
orbitalOpt.InitCoes Symmetrical # Symmetrical|Free
orbitalOpt.initPrefactor 0.1 # default=0.1
orbitalOpt.scf.maxIter 15 # default=12
orbitalOpt.MD.maxIter 10 # default=5
orbitalOpt.per.MDIter 10000 # default=1000000
orbitalOpt.criterion 1.0e-4 # default=1.0e-4 (Hartree/borh)^2

scf.dftD on # on|off, default=off
version.dftD 3 # 2|3, default=2
DFTD3.damp bj # zero|bj, default=bj
DFTD.Unit AU # Ang|AU
DFTD.rcut_dftD 100.0 # default=100 (DFTD.Unit)
DFTD.cncut_dftD 40 # default=40 (DFTD.Unit)
DFTD.IntDirection 1 1 1 # default=1 1 1 (1:on 0:off)
# Band dispersion
#

Band.dispersion on # on|off, default=off
Band.Nkpath 3
<Band.kpath
100 0.5 0.0 0.0 0.0 0.0 0.0 M G
100 0.0 0.0 0.0 0.34 0.34 0.0 G K
100 0.34 0.34 0.0 0.5 0.0 0.0 K M
Band.kpath>

# DOS and PDOS
#

DosGauss.fileout off # on|off , default=off
DosGauss.Num.Mesh 500 # default=200
DosGauss.Width 0.06 # default=0.2(eV)

Dos.fileout on # on|off, default=off
Dos.Erange -1.0 1.0 # default = -20 (eV) 20 (eV)
Dos.Kgrid 100 100 1 # default = Kgrid1 Kgrid2 Kgrid3
FermiSurfer.fileout on # default = off, on/off


MD.Type nomd
MD.maxIter 1
MD.TimeStep 1.0
MD.Opt.criterion 0.0003
HS.fileout on


As you can see the following necessary tags are according to the requirement:

scf.SpinPolarization nc
scf.SpinOrbit.Coupling on
HS.fileout on

I got the scfout file after the successful calculation. This is the first few lines of my System.Band file-->

130 0 -0.168679680241204
1.020037701724829 0.588919041685114 -0.000000000000000 0.000000000000000 1.177838083336324 0.000000000000000 0.000000000000000 -0.000000000000000 0.099475787166726
3
100 0.500000000000000 0.000000000000000 0.000000000000000 0.000000000000000 0.000000000000000 0.000000000000000 M G
100 0.000000000000000 0.000000000000000 0.000000000000000 0.340000000000000 0.340000000000000 0.000000000000000 G K
100 0.340000000000000 0.340000000000000 0.000000000000000 0.500000000000000 0.000000000000000 0.000000000000000 K M
130 0.500000000000000 0.000000000000000 0.000000000000000
-2.411498267423601 -2.411498263537847 -1.524949986464284 -1.524949982070253 -1.437278362550993 -1.437278358612342 -1.4322644689

We can see there are 130 bands.

After this calculation I updated my system.dat file with the FermiLoop tag on:

# Spin textures; Mulliken population
#

Filename.scfout System.scfout # default: default
Filename.outdata System_FL # default: default
Calc.Type FermiLoop # default: MulPOnly
Energy.Range -0.5 0.5 # eV; default: -0.5 0.5
Search.kCentral 0.0 0.0 0.0 # default: 0.0 0.0 0.0
Calc.Type.3mesh 2 # default: 1
kRange.3mesh 0.16 0.16 # default: 0.5 0.5
k-plane.1stStep 25 25 # default: 2 2
k-plane.2ndStep 2 2 # default: 3 3
Eigen.Brent On # default: On
Trial.Brent 5 # default: 5
Calc.Bandbyband on # default: Off
Calc.Band.Min 10
Calc.Band.Max 11
MulP.Vec.Scale 0.1 0.1 0.1 # default: 1.0 1.0 1.0
Filename.atomMulP System_FL.AtomMulP # default: default
Filename.xyzdata System_FL_MC # default: default

I provided the random values for Calc.Band.Min(10) and Calc.Band.Max(11) and used the command "./kSpin System.dat".

It showed me an error :
Start "FermiLoop" Calculation (5).

########### ORBITAL DATA ##################
ClaOrb_MAX[0]: 3
ClaOrb_MAX[1]: 15
Total Band (2*n): 130
Central ( 0.000000 0.000000 0.000000)
###########################################

########### EIGEN VALUE ###################
Error: No Bands are found.
############ CALC TIME ####################
Total Calculation Time: 27.391147 (s)
###########################################

Would you please suggest me what mistake I am making?
Should I run this Fermiloop calculation along with my initial scf calculation?

Thank you


メンテ
Page: [1]

Re: kSpin Error: No Bands are Found ( No.1 )
Date: 2021/06/09 20:04
Name: Naoya Yamaguchi

Dear Simba,

This error appears when the FermiLoop calculation failed to find bands.

To solve it, you need to give appropriate values for the input keywords related to the kSpin.

First, please check if there are bands within -0.5 eV and 0.5 eV.
Second, please try turning off the switch of `Calc.Bandbyband`. Your setting of `Calc.Band.Min 10` and `Calc.Band.Max 11` might cause the problem because bands 10 and 11 might be very deep energy levels apart from the Fermi level.
Third, please extend the searching k-plane by setting a default setting of `kRange.3mesh 0.5 0.5`.

Regards,
Naoya Yamaguchi
メンテ
Re: kSpin Error: No Bands are Found ( No.2 )
Date: 2021/06/14 12:37
Name: Simba  <pshubham2805@gmail.com>

Dear Sir,

I tried many configurations

# Spin textures; Mulliken population
#

Filename.scfout System.scfout # default: default
Filename.outdata System_FL # default: default
Calc.Type FermiLoop # default: MulPOnly
Energy.Range -0.5 0.5 # eV; default: -0.5 0.5
Search.kCentral 0.0 0.0 0.0 # default: 0.0 0.0 0.0
Calc.Type.3mesh 2 # default: 1
kRange.3mesh 0.5 0.5 # default: 0.5 0.5
k-plane.1stStep 25 25 # default: 2 2
k-plane.2ndStep 2 2 # default: 3 3
Eigen.Brent On # default: On
Trial.Brent 5 # default: 5
Calc.Bandbyband off # default: Off
Calc.Band.Min 10
Calc.Band.Max 11
MulP.Vec.Scale 0.1 0.1 0.1 # default: 1.0 1.0 1.0
Filename.atomMulP System_FL.AtomMulP # default: default
Filename.xyzdata System_FL_MC # default: default

And yes there are bands ranging from -78eV to 124eV and also in the range -0.5 to 0.5. There is a Rashba splitting at Gamma point.

I tried setting
kRange.3mesh 0.16 0.16

also tried with increasing energy range

Energy.Range -1 1.

switched off this: Calc.Bandbyband off # default: Off

メンテ
Re: kSpin Error: No Bands are Found ( No.3 )
Date: 2021/06/14 16:11
Name: Naoya Yamaguchi

Dear Simba,

>There is a Rashba splitting at Gamma point.
Where is the splitting in the unit of eV?

Regards,
Naoya Yamaguchi
メンテ
Re: kSpin Error: No Bands are Found ( No.4 )
Date: 2021/06/14 16:18
Name: Simba  <pshubham2805@gmail.com>

it is at -0.011052008232.
メンテ
Re: kSpin Error: No Bands are Found ( No.5 )
Date: 2021/06/14 18:27
Name: Naoya Yamaguchi

Dear Simba,

>it is at -0.011052008232.
`Energy.Range -1 1` is true. Then, how large is the Rashba momentum offset k_R?

Regards,
Naoya Yamaguchi
メンテ
Re: kSpin Error: No Bands are Found ( No.6 )
Date: 2021/06/14 18:37
Name: Naoya Yamaguchi

Dear Simba,

In addition, can you show the reciprocal lattice vectors?

Regards,
Naoya Yamaguchi
メンテ
Re: kSpin Error: No Bands are Found ( No.7 )
Date: 2021/06/14 18:40
Name: Simba  <pshubham2805@gmail.com>

k_R = 0.0271 bohr^(-1).
Basically, Gamma is at 1.008114 bohr^(-1). and maxima of the band is at 0.980964 bohr^(-1).
Subtracting them gives k_R = 0.0271 bohr^(-1).

and E_R = -0.011052008232 - (-0.004904200462) = 0.0061eV
メンテ
Re: kSpin Error: No Bands are Found ( No.8 )
Date: 2021/06/14 18:44
Name: Simba  <pshubham2805@gmail.com>

I have not defined Reciprocal lattice vectors in my day file. Where do I get them? Or do I need to calculate them manually?
メンテ
Re: kSpin Error: No Bands are Found ( No.9 )
Date: 2021/06/14 18:53
Name: Naoya Yamaguchi

Dear Simba,

It is shown in the standard output.
The following an example.
reciprocal lattice vectors (bohr^-1)
RA = 0.066498374316, 0.000000000000, 0.000000000000
RB = 0.000000000000, 0.066498374316, 0.000000000000
RC = 0.000000000000, 0.000000000000, 0.066498374316

Regards,
Naoya Yamaguchi
メンテ
Re: kSpin Error: No Bands are Found ( No.10 )
Date: 2021/06/14 19:00
Name: Naoya Yamaguchi

Dear Simba,

Or, please paste the first four lines of the `atominfo` file.
http://www.openmx-square.org/openmx_man3.9/node176.html

Regards,
Naoya Yamaguchi
メンテ
Re: kSpin Error: No Bands are Found ( No.11 )
Date: 2021/06/14 19:14
Name: Simba  <pshubham2805@gmail.com>

It is my Reciprocal Lattice

reciprocal lattice vectors (bohr^-1)
RA = 0.988156899914, 0.570512645479, -0.000000000000
RB = 0.000000000000, 1.141025290958, 0.000000000000
RC = 0.000000000000, -0.000000000000, 0.072981202586
メンテ
Re: kSpin Error: No Bands are Found ( No.12 )
Date: 2021/06/14 19:31
Name: Naoya Yamaguchi

Dear Simba,

If you focus on the k-plane along the two reciprocal vectors `RA` and `RB`,
(0.0271/1.141025290958)~0.02375 in the fractional coordinate.
And, in this case, you need to set 1 to `Calc.Type.3mesh`, not 2.
(Please also see `Calc.Type.3mesh` in http://www.openmx-square.org/openmx_man3.9/node176.html)
You need to increase `k-plane.1stStep` or set smaller value but not too small value to `kRange.3mesh`.
For example, `k-plane.1stStep 100 100` and `kRange.3mesh 0.5 0.5`, or `k-plane.1stStep 25 25` and `kRange.3mesh 0.1 0.1`.
(For the detail, please see pages 6-10 in http://www.openmx-square.org/tech_notes/note_kSpin-1_0.pdf)

Regards,
Naoya Yamaguchi
メンテ
Re: kSpin Error: No Bands are Found ( No.13 )
Date: 2021/06/14 19:54
Name: Simba  <pshubham2805@gmail.com>

Thank you so much for your references.

Now I am using this:

Filename.scfout System.scfout # default: default
Filename.outdata System_FL # default: default
Calc.Type FermiLoop # default: MulPOnly
Energy.Range -1 1 # eV; default: -0.5 0.5
Search.kCentral 0.0 0.0 0.0 # default: 0.0 0.0 0.0
Calc.Type.3mesh 1 # default: 1
kRange.3mesh 0.1 0.1 # default: 0.5 0.5
k-plane.1stStep 25 25 # default: 2 2
k-plane.2ndStep 2 2 # default: 3 3
Eigen.Brent On # default: On
Trial.Brent 5 # default: 5
Calc.Bandbyband off # default: Off
Calc.Band.Min 10
Calc.Band.Max 11
MulP.Vec.Scale 0.1 0.1 0.1 # default: 1.0 1.0 1.0
Filename.atomMulP System_FL.AtomMulP # default: default
Filename.xyzdata System_FL_MC # default: default
Num.of.Extract.Atom 4 # default: 1
Extract.Atom 1 2 3 4 # default: 1 2 ... (Num.of.Extract.Atom)
Data.Reduction 6 # default: 1

Even this is not working.

メンテ
Re: kSpin Error: No Bands are Found ( No.14 )
Date: 2021/06/14 20:05
Name: Naoya Yamaguchi

Dear Simba,

Now, you can adjust values for the following keywords.
Energy.Range
kRange.3mesh
k-plane.1stStep
k-plane.2ndStep

`k-plane.2ndStep` is a keyword after some bands are found, and `Energy.Range` is enough according to No. 7. And, `kRange.3mesh` may be good.
So, please increase values for `k-plane.1stStep` unless bands are found.

Regards,
Naoya Yamaguchi
メンテ
Re: kSpin Error: No Bands are Found ( No.15 )
Date: 2021/06/14 22:13
Name: Simba  <pshubham2805@gmail.com>

Ahh, Now I am getting something. I see that there is only one band is plotted, took one hour.

########### EIGEN VALUE ###################
The number of BANDs 1 ( 71-> 71)
########### CONTOUR CALC ##################
k-height : 0 0.000000
The number of BANDs 1 ( 71-> 71)
l= 71, k_points: 62 (array: 121)
Total MulP data: 62
###########################################

###########################################

############ CALC TIME ####################
Total Calculation Time:3766.910983 (s)
Eigen Value Calc:3589.290980 (s)
l= 71: Contour Calc:153.001995 (s)
MulP Calc: 24.483195 (s)



I set my parameters as

Energy.Range -1 1 # eV; default: -0.5 0.5
Search.kCentral 0.0 0.0 0.0 # default: 0.0 0.0 0.0
Calc.Type.3mesh 1 # default: 1
kRange.3mesh 0.1 0.1 # default: 0.5 0.5
k-plane.1stStep 100 100 # default: 2 2
k-plane.2ndStep 2 2 # default: 3 3

I plotted the *.plotexample file it gives me two circles that are not clearly visible.

The range of x and y-axes are -0.8 0.8 and -1.2 1.2.
the origin of one circle is around (-0.7, -1.1) and another (0.7, 1.1).
Is this spin texture?
メンテ
Re: kSpin Error: No Bands are Found ( No.16 )
Date: 2021/06/15 01:07
Name: Naoya Yamaguchi

Dear Simba,

Sorry, I explained by mistake that `Energy.Range` was a range of energies. In `FermiLoop` the `Energy.Range` is an energy height to cut a plane, not a range.

>The range of x and y-axes are -0.8 0.8 and -1.2 1.2.
>the origin of one circle is around (-0.7, -1.1) and another (0.7, 1.1).
>Is this spin texture?
It is different from what you focus on.

>Basically, Gamma is at 1.008114 bohr^(-1). and maxima of the band is at 0.980964 bohr^(-1).
>Subtracting them gives k_R = 0.0271 bohr^(-1).
>
>and E_R = -0.011052008232 - (-0.004904200462) = 0.0061eV

When different two values are set to `Energy.Range` in `FermiLoop`, the averaged value is set.
So, `Energy.Range -1 1` sets a plane of 0 eV, but the maxima is lower than it so that the values for `Energy.Range` so far were too high.
You may specify lower values for `Energy.Range` such as `-0.5 -0.5` and `-1.0 -1.0`.

Regards,
Naoya Yamaguchi
メンテ

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