Messages

1

General Questions and Answers / scf convergence for finite bias device calculation

« on: February 4, 2021, 10:30 »

my zero bias calculation for both parallel and anti-parallel configuration, as well as finite bias 0.05v calculation for parallel configuration, converges well, but when I do 0.05V calculation for anti-parallel geometry, the calculation doesn't converge at all. I have used the zero bias calculation as the initial state for the finite bias 0.05V calculation and damping factor 0.05, history steps 12. I have attached my script file for your reference.

2

General Questions and Answers / Re: IV curve calculation did not converge after 0.4v bias

« on: June 3, 2019, 11:38 »

I guess it's the num_histoty_steps that is creating problem in convergence, I reduced the k-point to na=13, nb=7, and nc=141 and num_history_steps=12. The zero bias calculation converged in 147 steps, but 0.05V, 0.3V, 0.35V, 0.4V bias doesn't converge to the requested tolerance of 1E-06 in 200 steps. The detailed log file is attached



../ivcurve_0.10000V.log:| Calculation Converged in 165 steps                                           |
../ivcurve_0.15000V.log:| Calculation Converged in 116 steps                                           |
../ivcurve_0.20000V.log:| Calculation Converged in 123 steps                                           |
../ivcurve_0.25000V.log:| Calculation Converged in 91 steps                                            |
../trans_195612.log:| Calculation Converged in 21 steps                                            |
../trans_195612.log:| Calculation Converged in 45 steps                                            |
../trans_195612.log:| Calculation Converged in 147 steps


ivcurve_0.05000V.log:# Warning: The calculation did not converge to the requested tolerance!        #
ivcurve_0.30000V.log:# Warning: The calculation did not converge to the requested tolerance!        #
ivcurve_0.35000V.log:# Warning: The calculation did not converge to the requested tolerance!        #
ivcurve_0.40000V.log:# Warning: The calculation did not converge to the requested tolerance!        #

3

General Questions and Answers / Re: IV curve calculation did not converge after 0.4v bias

« on: May 30, 2019, 06:54 »

As suggested by you, I tried K-point= 18, 10 and 300, damping factor 0.05, history steps 12 and equivalent bulk method. The calculation for zero bias converged in 115 steps, 0.05 V in 36 steps, but for bias 0.1V it didn't converge to the requested tolerance of 1E-05 in 200 steps.

4

General Questions and Answers / Re: How to calculate current value from the finite-bias transmission spectrum

« on: May 26, 2019, 07:31 »

Just select all the transmission spectrum .hdf5 files for different bias and use the IV generator tool for calculating the current for different biases.

5

General Questions and Answers / IV curve calculation did not converge after 0.4v bias

« on: May 26, 2019, 07:14 »

I am trying to calculate IV curve fore MTJ .  The calculation is not converging after bias of 0.4V. I have used DZP basis set for all the elements and have kept damping factor to 0.05.

6

General Questions and Answers / Re: I_V curve calculation did not converge after 0.2V bias

« on: October 31, 2018, 14:31 »

I have followed the above mentioned guide. I have used equivalent bulk method also, k-point along C direction is 141. you can have a look at the attached input script for detail inputs given by me. If anything wrong please suggest. I have observed that charges build up near the electrode(lower index atom and highest index atoms). please suggest for improvement.

7

General Questions and Answers / I_V curve calculation did not converge after 0.2V bias

« on: October 31, 2018, 14:02 »

My IV curve calculation is not converging after bias of 0.2V. In device structure, I have a substitutional doped Cr atom in cental region(3 layer of MoS2). Calculation with no doping is converging well but not with doped structure.