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31

General Questions and Answers / bulk InSe band gap is wrong in the 2017.a2 version

« on: May 29, 2017, 09:57 »

Hi all

i tried the newest version 2017.a2 to calculate the band gap of bulk Inse.

I used GGA-PBE. as we know, the local EXC-Function will underestimate the band gap, but my results is opposite, which is 1.35eV, While the experimental value is 0.5eV

i test the calculation with the older version such 13.8.1, the band gap is almost the same with the experimental value.

so i am wondering what cause the error.

please help me.

thanks very much

32

General Questions and Answers / how to choose the R e al a xis p oin t d e n sit y?

« on: September 3, 2016, 15:57 »

Hi all:

I read the following tutorial: http://docs.quantumwise.com/_downloads/atk_transport_calculations.pdf

NEGF contour integral NEGF contour integral For finite-bias calculations, a potentially important convergence parameter is the R e al a xis p oin t d e n sit y , which is specified under C o n t o u r in t e g r al p a r a m e t e r s . This parameter determines how many energy points are used when integrating the left and right spectral density matrices along the real energy axis between the chemical potentials of the left and right electrodes. For the present calculation you can proceed with the default value, but be aware that a convergence test of this parameter should in general be performed.

so, if the self-consistent calculation of device under bias did not converge? should I increase the real axis point density to see the results?

33

General Questions and Answers / the scf of iv-curve in some bias did not convengency, some did converge

« on: August 31, 2016, 04:03 »

Hi :
I calculated the iv-curve under 0-2 V, But I found under 1.4,1.6,0.6,0.4.0.2 V the scf calculation did converge, but other bias point did not converge such 0.8,1.0.1.2 .1.8.2.0.
217 S [ 3.337 , 19.732 , 67.456 ] 6.82742 0.82742 |
| 218 S [ 2.275 , 23.070 , 67.460 ] 6.36327 0.36327 |
| 219 S [ 4.364 , 23.102 , 67.461 ] 6.36487 0.36487 |
+------------------------------------------------------------------------------+
| 99 E = -356.72 dE = 3.048208e-04 dH = 1.026967e-02 |
+------------------------------------------------------------------------------+
################################################################################
# #
# Warning: The calculation did not converge to the requested tolerance! #
# #
################################################################################
+------------------------------------------------------------------------------+
| |
| NEGF DFT Calculation [Finished Sat Aug 27 18:33:23 2016] |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Device DFT Calculation [Finished Sat Aug 27 18:33:23 2016] |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Transmission Spectrum Analysis |
| |
+------------------------------------------------------------------------------+

|--------------------------------------------------|
Calculating Transmission : ==================================================

so I am wondering how to set the parameter to continue to recalculated the transmission spectrum under converge bias 0.8,1.0.1.2 and 1.8.2.0 V.
my current calculation only has one checkpoint file which including the whole bias 0-2 V.

34

General Questions and Answers / the electrics difference potential （ EDP） of MGGA results are trustfuL or GGA ?

« on: August 29, 2016, 12:05 »

Hi
I am calculated the electrics difference potential with same interface, but I found the deltV between the two atoms layer is opposite, so I am wondering the MGGA can calculate the EDP？
ps： my interface is two slab, the MGGA c parameter has fixed to some value to fitting the GW gap, and the warning of MGGA is
The computed TB09 meta-GGA exchange-correlation potential #
# diverged in 0.01 % of the simulation volume, and was #
# truncated to be in the range [-10.0000, 10.0000] Hartree

so I am wounding the MGGA result for the EDP is trustful or GGA results is trustful.

35

General Questions and Answers / the memory usage is too large to complte the iv-calculation

« on: August 27, 2016, 04:18 »

Hi all

I am using ATK 2016, but I found the memory is used too large when I calculated the iv curve under bias, the calculation is always crash.

is there method or setting to reduce the memory but not to reduce calculation precision during calculation please help me.

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
10126 MSI 20 0 7257m 6.6g 35m R 100.0 21.3 1109:38 atkpython
10127 MSI 20 0 7348m 6.7g 34m R 100.0 21.5 1109:38 atkpython
10125 MSI 20 0 7188m 6.6g 37m R 98.3 21.0 1109:44 atkpython
10128 MSI 20 0 7165m 6.5g 37m R 98.3 20.7 1109:43 atkpython

36

General Questions and Answers / iv-curve calculation stoped with error in atk2016

« on: August 25, 2016, 02:33 »

Hi
i used ATK 2016, i want to calculated the iv curve at 0~2 V, using the *.nc at 0 V bias , but the calculation process interupt, the log said:

+------------------------------------------------------------------------------+
| |
| Transmission Spectrum Analysis |
| |
+------------------------------------------------------------------------------+

|--------------------------------------------------|
Calculating Transmission : ==================================================

+------------------------------------------------------------------------------+
| IV-Curve Calculation |
+------------------------------------------------------------------------------+
| The current will be calculated at 10 points between 0.000 to 2.000 V. |
| Note: The current has already been calculated at 0.000 V. |
| Each bias point will be calculated using 4/4 MPI processes. |
| |
| Bias Point Process Group Log File |
| 0.200 0 ivcurve_0.20000V.log |
| 0.400 0 ivcurve_0.40000V.log |
| 0.600 0 ivcurve_0.60000V.log |
| 0.800 0 ivcurve_0.80000V.log |
| 1.000 0 ivcurve_1.00000V.log |
| 1.200 0 ivcurve_1.20000V.log |
| 1.400 0 ivcurve_1.40000V.log |
| 1.600 0 ivcurve_1.60000V.log |
| 1.800 0 ivcurve_1.80000V.log |
| 2.000 0 ivcurve_2.00000V.log |
+------------------------------------------------------------------------------+
rank 3 in job 5 node11_56242 caused collective abort of all ranks
exit status of rank 3: killed by signal 11

the outfile only has three :
ivcurve_0.20000V.log
ivcurve_0.40000V.log
ivcurve_0.60000V.log

i found the above three file, the calculation is not complete, all stopped:

+------------------------------------------------------------------------------+
| |
| NEGF DFT Calculation [Finished Wed Aug 24 16:56:55 2016] |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Device DFT Calculation [Finished Wed Aug 24 16:56:55 2016] |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Transmission Spectrum Analysis |
| |
+------------------------------------------------------------------------------+

|--------------------------------------------------|
Calculating Transmission : ==================================================

so i am wondering what happened? is it memory problem?or would i complete my iv calculation?

37

General Questions and Answers / how to extract the subthreshold swing (SS)

« on: August 23, 2016, 13:57 »

Hi :

i am facing how to get the subthrshold swing when i calculated the gated device, i found there are one formular(see attachment):

as we know, ATK software can directly get Id at some Vg, so i think the first equation is convenient for me.
but i am wondering at which Vd, should i calculated Id vs.Vg?
some reference said Vd is the drain biased at saturation, some reference said set x eV , not specified why choose the Vd,

So, would anyone tell me how to choose Vd, it is necessary it is saturation?

thanks very much!!

38

General Questions and Answers / VNL.EXE STOP working when i want to see the PDOS OF DEVICE

« on: August 21, 2016, 15:12 »

HI,
I USE THE atk-2016, when I open the D(E), the VNL says the VNL.EXE will stop, the window will shut up the exe...., my system is WIN10.
has anyone face the same problem?

39

General Questions and Answers / the k-sampling understanding of NiSi2–Si interface documment in the tutorial

« on: August 18, 2016, 07:22 »

Hi all:

i am reading the "NiSi2–Si interface" in http://docs.quantumwise.com/tutorials/nisi2-si/nisi2-si.html， accrording my undstanding the interface Nisi2-si is 2D slabs, so the k sampling in the x-drection(vacu) should be setted to 1(see figure), why in the documnet the k point in the x is setting to 25, which is the same with that in the y periodic direction.(see figure)

is there anyone can help me undstand this issue

thanks very much!

40

General Questions and Answers / MGGA is suitable for the transport calculation of two-probe configuration

« on: August 17, 2016, 15:22 »

Hi all:

i saw MGGA can give reasonable band gap for bulk, my question is that it is suitable for the transport calulation of two-probe configuration,because i want to get reasonalbe band gap in the transmission spectrum.

thanks very much!!

best wishes

41

**General Questions and Answers / how to write python code for read bulk configuration from *.car file**

« on: June 16, 2016, 11:12 »

Hi all:

i know that nlread function can read car file, but i do not know how to write any continue code to specify the what is bulk_configuration, bravais_lattice and so on similar with the following :
# Set up configuration
bulk_configuration = BulkConfiguration(
bravais_lattice=lattice,
elements=elements,
fractional_coordinates=fractional_coordinates
)

is any can kindly help me.

best wishes

42

General Questions and Answers / how to set "the mettallic contact is taken as an electron gas with fixed chemi"

« on: May 18, 2016, 10:21 »

Dear All:

i saw a reference <<Effect ofhalide-mixingontheelectronictransportproperties of organometallicperovskites>>; in that paper, there is a word "the mettallic contact is taken as an electron gas with fixed chemical potential" so i am wondering how to set the metallic contact with some chemical potential, because the transmission spetrum is done by ATK in that paper.
is there anyone can help me?

43

General Questions and Answers / is channel length can influence the gate effect?

« on: April 6, 2016, 04:24 »

Hi all:

i have a question about the gate effect , my metal layer thickness is increased to 13 angstrom, but when i add gate voltage to 13 V, the band gap was shift so small, so i am wondering whether the channel length 35 angstrom is too short? the channle length can influnece gate effect?

my two-probe system is attached, the Transmission spectrum at gate 0v and 13 v are also included,

is anyone can help to find the cause why the gate effect so small, my aim is to get a high off-on ration,

44

General Questions and Answers / UnboundLocalError: local variable 'periodicity' referenced before assignment

« on: March 8, 2016, 03:42 »

Hi :
i face a relax problem, the error log is

Traceback (most recent call last):
File "./relax-Device-fr-relaxed-D3-five-layer-Au-fix-bottom-3layer-fr-relaxed-Au-111-by-vasp-fr-relaxed-Au-by-vasp-change-a-b-POSCAR-relaxed-by-liming.py", line 802, in <module>
optimizer_method=LBFGS(),
File "./zipdir/NL/Dynamics/Optimization/OptimizeGeometry.py", line 331, in OptimizeGeometry
File "./zipdir/NL/Dynamics/Optimization/OptimizeGeometry.py", line 467, in runSimultaneousRelaxation
File "./zipdir/NL/Dynamics/Optimization/OptimizeGeometry.py", line 376, in runRelaxation
File "./zipdir/NL/Dynamics/ASEAtomsInterface.py", line 289, in get_forces
File "./zipdir/NL/Dynamics/ASEAtomsInterface.py", line 164, in _update
File "./zipdir/NL/Calculators/LCAOCalculator/Analysis/FastEnergyForcesStress.py", line 34, in energyFunction
File "./zipdir/NL/Calculators/LCAOCalculator/Analysis/FastEnergyForcesStress.py", line 71, in _checkAndUpdate
File "./zipdir/NL/Calculators/LCAOCalculator/Analysis/FastEnergyForcesStress.py", line 107, in _update
File "./zipdir/NL/ComputerScienceUtilities/Timer.py", line 45, in __call__
File "./zipdir/NL/Calculators/LCAOCalculator/Analysis/FastEnergyForcesStress.py", line 106, in <lambda>
File "./zipdir/NL/Calculators/LCAOCalculator/Analysis/EnergyForcesStress.py", line 254, in calculateLCAOEnergyForcesStress
File "./zipdir/NL/Calculators/GenericParameters/GrimmeDFTD3.py", line 461, in _adjustStress
File "./zipdir/NL/Calculators/GenericParameters/GrimmeDFTD3.py", line 495, in _calculateCorrections
File "./zipdir/NL/Calculators/GenericParameters/GrimmeDFTD3.py", line 670, in __buildCPPObjects
UnboundLocalError: local variable 'periodicity' referenced before assignment

and at the end of output file, , there are information below, i don not konw whether the relax is complete or not, because there are words: Calculation Converged in 17 steps , does it meaming the relaxed is complete or not?

+------------------------------------------------------------------------------+
| |
| Size of dense matrices = 3060 x 3060 [143 MB per matrix] |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| 213 Au [ 2.079 , 14.792 , 66.928 ] 10.98515 -0.01485 |
| 214 Au [ 0.840 , 9.714 , 66.939 ] 11.01089 0.01089 |
| 215 Au [ 4.116 , 12.264 , 66.939 ] 10.98587 -0.01413 |
| 216 Ti [ 0.859 , 18.756 , 67.452 ] 3.86359 -0.13641 |
| 217 S [ 3.337 , 19.732 , 67.456 ] 6.08704 0.08704 |
| 218 S [ 2.275 , 23.070 , 67.460 ] 5.98240 -0.01760 |
| 219 S [ 4.364 , 23.102 , 67.461 ] 5.99040 -0.00960 |
+------------------------------------------------------------------------------+
| 17 E = -503.204 dE = 9.084030e-05 dH = 3.281213e-05 |
+------------------------------------------------------------------------------+
| Calculation Converged in 17 steps |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Device DFT Calculation [Finished Mon Mar 7 16:30:18 2016] |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Size of dense matrices = 3060 x 3060 [143 MB per matrix] |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Storage of orbitals in real space is disabled. |
| Enabling storage requires an additional 1177 MB. |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Real space grid sampling is (37, 374, 502) in a, b, and c directions. |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Real space grid sampling is (37, 374, 101) in a, b, and c directions. |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Size of dense matrices = 882 x 882 [12 MB per matrix] |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Real space grid sampling is (37, 374, 101) in a, b, and c directions. |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Storage of atomic core grids requires 10 MB per grid |
| |
+------------------------------------------------------------------------------+

+------------------------------------------------------------------------------+
| |
| Real space grid sampling is (37, 374, 101) in a, b, and c directions. |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Size of dense matrices = 882 x 882 [12 MB per matrix] |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Real space grid sampling is (37, 374, 101) in a, b, and c directions. |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Storage of atomic core grids requires 10 MB per grid |
| |
+------------------------------------------------------------------------------+

+------------------------------------------------------------------------------+
| |
| Real space grid sampling is (37, 374, 101) in a, b, and c directions. |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Size of dense matrices = 3060 x 3060 [143 MB per matrix] |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Real space grid sampling is (37, 374, 101) in a, b, and c directions. |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Size of dense matrices = 3060 x 3060 [143 MB per matrix] |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Storage of atomic core grids requires 52 MB per grid |
| |
+------------------------------------------------------------------------------+

+------------------------------------------------------------------------------+
| |
| Real space grid sampling is (37, 374, 101) in a, b, and c directions. |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Storage of atomic core grids requires 10 MB per grid |
| |
+------------------------------------------------------------------------------+

+------------------------------------------------------------------------------+
| |
| Real space grid sampling is (37, 374, 101) in a, b, and c directions. |
| |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| |
| Storage of atomic core grids requires 10 MB per grid |
| |
+------------------------------------------------------------------------------+

| Left electrode chemical potential = -4.019404 eV |
| Right electrode chemical potential = -4.019404 eV |
+------------------------------------------------------------------------------+

|--------------------------------------------------|
Calculating Density Matrix : ==================================================

|--------------------------------------------------|
Calculating Kinetic Matrix : ==================================================

|--------------------------------------------------|
Calculating Kinetic Matrix : ==================================================

|--------------------------------------------------|
Calculating Kinetic Matrix : ==================================================

|--------------------------------------------------|
Calculating Kinetic Matrix : ==================================================

|--------------------------------------------------|
Calculating Nonlocal Part : ==================================================

|--------------------------------------------------|
Calculating Nonlocal Part : ==================================================

|--------------------------------------------------|
Calculating Nonlocal Part : ==================================================

|--------------------------------------------------|
Calculating Nonlocal Part : ==================================================

Timing: Total Per Step %

--------------------------------------------------------------------------------

Diagonalization : 84569.99 s 1595.66 s 66.94% |=============|
Density Matrix : 26163.15 s 1453.51 s 20.71% |===|
Setting Density Matrix : 22052.99 s 7351.00 s 17.46% |===|
Exchange-Correlation : 1690.38 s 22.84 s 1.34% |
Real Space Integral : 599.67 s 8.10 s 0.47% |
Valence Density : 483.24 s 6.53 s 0.38% |
Hartree Potential : 212.15 s 2.87 s 0.17% |
Mixing : 17.42 s 0.25 s 0.01% |
Constant Terms : 15.87 s 7.93 s 0.01% |
Difference Density : 12.14 s 0.22 s 0.01% |
Real Space Basis : 9.70 s 3.23 s 0.01% |
Loading Modules + MPI : 3.95 s 3.95 s 0.00% |
Core Density : 3.66 s 0.07 s 0.00% |
Neutral Atom Potential : 3.41 s 1.70 s 0.00% |
Basis Set Generation : 2.30 s 0.77 s 0.00% |
File IO, nlsave : 0.24 s 0.24 s 0.00% |
Hubbard Term : 0.00 s 0.00 s 0.00% |
Fixed Spins Term : 0.00 s 0.00 s 0.00% |
--------------------------------------------------------------------------------
Total : 126329.92 s (1d11h05m29.92s)

===================================================================================
= BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES
= EXIT CODE: 1
= CLEANING UP REMAINING PROCESSES
= YOU CAN IGNORE THE BELOW CLEANUP MESSAGES
===================================================================================

45

General Questions and Answers / can ATK find semiconductor contribution to the bandstructure in the interface

« on: February 18, 2016, 08:52 »

how all:
i am simulating the the graphdiyne on the Ag (111), and want to find the schottky barrier of the such a semicondutor-metal contact,
i am finding some reference plot the band-structure of graphdiyne on the Ag (111) (see Figure), by identifying the graphdiyne contribution to the bans structure, locate the Fermi level shift to conduct band and then comparing the pristine graphdiyne, thus give the schottky barrier, so i want to know how to identify the contribution of graphdiyne to the bandstructure in the semiconductor-metal interface in the ATK?

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