Messages

16

General Questions and Answers / Re: Can ATK calculate local DOS of a bulk configuration?

« on: September 3, 2019, 17:03 »

The related material is a WTe2 nanoribbon, which is periodic only along C direction. It's non-periodic along B direction and has a limited width along this direction. Thus, is it possible for ATK to distinguish and calculate the localized DOS for the edge and central region of the nanoribbon?

17

General Questions and Answers / Can ATK calculate local DOS of a bulk configuration?

« on: September 3, 2019, 15:21 »

Dear experts,

I got the photo attached in this topic from the ref: NATUREPHYSICS | VOL13 | JULY2017 Quantum spin Hall state in monolayer 1T’-WTe2. It seems to have provided the edge DOS and bulk DOS at the same time. I wonder if ATK can do the same job. And how? As to my knowledge, the PLDOS block can only work for device configuration.

Thank you for your concerning!


lknife

18

General Questions and Answers / Re: something wrong with the DOS block (2019.03)

« on: June 17, 2019, 08:54 »

Thank you very much for your kind reply!

There is another problem about the DOS block. I tried to analysis the data of DOS. However, every time when I selected some atoms on the right panel showing the configuration, the DOS analyzer got stuck and was forced quit. It appeared many times no matter how I tried to avoid this problem. Now, I have to use the PDOS block instead of the DOS block to do the simulation. This problem did not appear  in the early version of ATK, such as 2017 or 2018. Could you please check it?

19

General Questions and Answers / something wrong with the DOS block (2019.03)

« on: June 12, 2019, 03:28 »

Hi, ATK experts,

     Recently I failed several time when calculating the DOS of a bulk material. The ATK version I am using is 2019.03. I  tried to run the calculation using a local machine and a computer cluster but both failed. Attached are the .py file and .log file of one of the calculation. Can someone help me with this issue? Thank you very much for your concerning.

20

General Questions and Answers / Re: about the convergence of the IV calculation

« on: March 14, 2019, 03:53 »

For device convergence issues, please take a look at these notes https://docs.quantumatk.com/technicalnotes/negf_convergence_guide/negf_convergence_guide.html.

Thank you for your reply! I had read the guide before. However, I am still confused by so many options. Also, I am not sure if the IV curve is valid if the data on the curve are obtained using different convergence strategies.

21

General Questions and Answers / Re: about the convergence of the IV calculation

« on: March 12, 2019, 08:24 »

additional information:

I checked the .log file for some bias points. e. g. at bias 0.18V, 0.21V and 0.24V. Because of the size limit, I cannot attach the .log files. Instead, I post here the band energy (E) and the difference (dE) and Hamiltonian matrix elements (dH) of the last 30 SCF cycles.

For bias at 0.18V, it did not converge. The band energy (E) and the difference (dE) and Hamiltonian matrix elements (dH) were like below--
-----------------------------------------------------------------------------
| 170 E = -651.798 dE =  4.044902e-02 dM =  1.038161e-01 dH =  1.303229e+00    |
| 171 E =  -651.82 dE =  6.973168e-03 dM =  3.794980e-02 dH =  1.271307e+00    |
| 172 E =  -651.72 dE =  2.003298e-02 dM =  6.139546e-02 dH =  1.193302e+00    |
| 173 E = -651.622 dE =  1.387764e-02 dM =  4.281661e-02 dH =  1.060334e+00    |
| 174 E = -651.849 dE =  7.970397e-03 dM =  5.317894e-02 dH =  1.356581e+00    |
| 175 E =  -652.08 dE =  1.045167e-02 dM =  5.989330e-02 dH =  1.617708e+00    |
| 176 E = -651.601 dE =  1.316316e-02 dM =  8.908298e-02 dH =  1.117005e+00    |
| 177 E = -651.484 dE =  7.704034e-03 dM =  2.618570e-02 dH =  1.053042e+00    |
| 178 E = -651.487 dE =  7.129752e-03 dM =  3.691645e-02 dH =  1.139085e+00    |
| 179 E =  -651.27 dE =  1.189893e-02 dM =  6.756393e-02 dH =  9.374030e-01    |
| 180 E = -651.139 dE =  1.491213e-02 dM =  9.123284e-02 dH =  7.960077e-01    |
| 181 E = -651.049 dE =  4.868724e-03 dM =  1.342229e-02 dH =  7.873335e-01    |
| 182 E = -651.669 dE =  3.652773e-02 dM =  2.233291e-01 dH =  1.450075e+00    |
| 183 E = -651.298 dE =  4.110651e-02 dM =  2.106917e-01 dH =  8.166819e-01    |
| 184 E = -651.155 dE =  2.307643e-02 dM =  9.002607e-02 dH =  5.569482e-01    |
| 185 E =  -651.34 dE =  1.438901e-02 dM =  5.903590e-02 dH =  7.863402e-01    |
| 186 E = -652.389 dE =  9.476284e-02 dM =  3.559915e-01 dH =  2.182220e+00    |
| 187 E = -651.345 dE =  8.504621e-02 dM =  3.339246e-01 dH =  9.054757e-01    |
| 188 E = -651.492 dE =  1.757176e-02 dM =  7.981000e-02 dH =  7.091878e-01    |
| 189 E = -651.795 dE =  1.554410e-02 dM =  1.248392e-01 dH =  1.179052e+00    |
| 190 E = -651.612 dE =  1.267145e-02 dM =  1.126878e-01 dH =  9.885518e-01    |
| 191 E =  -651.03 dE =  3.537401e-02 dM =  2.072327e-01 dH =  1.250047e+00    |
| 192 E = -650.925 dE =  3.590851e-02 dM =  1.609478e-01 dH =  1.138320e+00    |
| 193 E = -650.759 dE =  1.579183e-02 dM =  7.361792e-02 dH =  8.462947e-01    |
| 194 E = -651.121 dE =  1.692964e-02 dM =  1.240033e-01 dH =  1.274886e+00    |
| 195 E = -650.785 dE =  2.565320e-02 dM =  1.908225e-01 dH =  8.584790e-01    |
| 196 E = -650.836 dE =  2.554568e-02 dM =  1.201435e-01 dH =  8.476001e-01    |
| 197 E = -650.806 dE =  6.826299e-03 dM =  2.917748e-02 dH =  8.480110e-01    |
| 198 E = -650.897 dE =  1.317645e-02 dM =  7.354966e-02 dH =  9.450469e-01    |
| 199 E = -651.211 dE =  1.030746e-02 dM =  5.507171e-02 dH =  1.119665e+00    |
------------------------------------------------------------------------------------------

While for bias at 0.21V, it looks like that the calculation became converged suddenly after the 64th SCF cycle.

|  56 E = -15.4467 dE =  2.979340e+00 dM =  8.417096e-02 dH =  5.858600e+01    |
|  57 E =  0.00635501 dE =  3.844430e+00 dM =  1.130846e+00 dH =  4.368325e+01 |
|  58 E = -12.5127 dE =  5.390223e+00 dM =  1.930463e-01 dH =  4.105452e+01    |
|  59 E =  0.00310733 dE =  5.390057e+00 dM =  1.930700e-01 dH =  1.893029e+01 |
|  60 E =  0.0764951 dE =  1.652323e-02 dM =  1.084730e-02 dH =  1.828765e+01  |
|  61 E =  0.00809108 dE =  1.658976e-02 dM =  2.095044e-02 dH =  1.616004e+01 |
|  62 E = -0.0803081 dE =  1.399932e-02 dM =  1.549542e-03 dH =  1.511367e+01  |
|  63 E = -7.52488 dE =  1.594457e+00 dM =  8.609775e-01 dH =  4.567215e+00    |
|  64 E = -0.0266777 dE =  1.599368e+00 dM =  8.625010e-01 dH =  3.453103e+00  |
|  65 E = -0.0147232 dE =  2.538757e-03 dM =  6.304485e-04 dH =  3.877150e+00  |
|  66 E = -0.0190753 dE =  7.759180e-04 dM =  3.252699e-05 dH =  3.630938e+00  |
|  67 E = -0.0104623 dE =  1.682583e-03 dM =  2.314317e-04 dH =  2.961721e+00  |
|  68 E = -0.0225712 dE =  2.457818e-03 dM =  4.489571e-04 dH =  2.611185e+00  |
|  69 E = -0.0126081 dE =  2.011628e-03 dM =  3.855940e-04 dH =  2.890064e+00  |
|  70 E = -0.0143453 dE =  3.408293e-04 dM =  1.152833e-04 dH =  6.236782e-01  |
|  71 E = -0.0160083 dE =  3.413112e-04 dM =  8.456062e-05 dH =  1.250041e-01  |
|  72 E = -0.015811 dE =  4.175172e-05 dM =  1.444087e-05 dH =  6.493140e-02   |
|  73 E = -0.0155582 dE =  5.125033e-05 dM =  7.791216e-06 dH =  5.607342e-02  |
|  74 E = -0.0158437 dE =  5.850811e-05 dM =  1.320131e-05 dH =  7.990641e-02  |
|  75 E = -0.0158074 dE =  7.601333e-06 dM =  5.263977e-06 dH =  3.829023e-02  |
|  76 E = -0.0156398 dE =  3.460024e-05 dM =  7.400740e-06 dH =  3.973113e-02  |
|  77 E = -0.0157361 dE =  1.943634e-05 dM =  3.812808e-06 dH =  2.234545e-02  |
|  78 E = -0.0156691 dE =  1.358503e-05 dM =  2.976237e-06 dH =  1.309541e-02  |
|  79 E = -0.0156911 dE =  4.653795e-06 dM =  1.348542e-06 dH =  4.449373e-03  |
|  80 E = -0.0156964 dE =  1.072482e-06 dM =  2.929692e-07 dH =  1.736597e-03  |
|  81 E = -0.0156972 dE =  1.891888e-07 dM =  2.617146e-08 dH =  5.071357e-04  |
|  82 E = -0.0156962 dE =  2.085112e-07 dM =  5.349786e-08 dH =  1.551410e-04  |
|  83 E = -0.0156962 dE =  5.215664e-09 dM =  2.899879e-09 dH =  3.090518e-05  |
|  84 E = -0.0156962 dE =  1.405080e-08 dM =  3.694223e-09 dH =  1.070665e-05  |
|  85 E = -0.0156962 dE =  4.027533e-11 dM =  1.433165e-11 dH =  1.021141e-05  |
|  86 E = -0.0156962 dE =  2.061471e-11 dM =  8.844481e-12 dH =  9.864005e-06  |
------------------------------------------------------------------------------------------

And for bias at 0.24V, since the calculation got converged at 0.21V, it got converged very quickly after just one SCF cycle. However, i don't think the current obtained is correct.
---------------------------------------------------------------------------------------
|   0 E = -92.9128 dE =  2.177833e-07 dM =  1.447770e-06 dH =  1.010501e-06    |
|   0 E = -92.8365 dE =  6.841815e-07 dM =  5.734264e-06 dH =  6.902065e-07    |
|   0 E = -0.0156952 dE =  1.784481e-07 dM =  1.012187e-08 dH =  7.222276e-09  |
----------------------------------------------------------------------------------------

22

General Questions and Answers / about the convergence of the IV calculation

« on: March 12, 2019, 03:58 »

Dear ATK experts,

I am suffering the convergence issues about the IV calculation. I am now using ATK 2018.6. When I tried to calculate the IV plot of a 2D lateral junction using Extended Huckel method, it cannot converge at many bias points. I have tried to increase the doping level (from 5*10¹⁹ to 1*10²⁰ ) , change the Poisson solver (Multigrid, Direct), the boundary condition,.... However, the issue still exist.

Please see attached the .py file and the IV plot obtained. Can anybody here help me about this problem? Thank you very much!