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Messages - Monika srivastava

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Dear Sir

I want to calculate the IV for the attached file of nanowire but it is not converging although in bulk form it has already converged. I have changed the k points, reduced step size, increased number of steps, reduced damping factor etc. but not able to converge to require tolerance.

I have also tried to compute the transmission spectrum but it has also not converged above 0.2V.

I have used two probe model for finding I-V

Thank you sir for replying

Please find the attachment of the script files

General Questions and Answers / I-V of graphene nanosheet
« on: May 27, 2021, 14:28 »
Hello sir

Is the number of repetition in graphene nanosheet affects the current or threshold voltage in current-voltage characteristics observed by modeling a two probe device model.

As it is well known that threshold voltage is decided by the band gap observed in density of states of the material but still I am getting two different curves for two different repetition.  one having 7 repetition shows increment of current from zero bias while one having repetition 11 shows some negative values of current and then start increasing around 0.15 V

thank you for the reply

But when i put the optimized geometry of oh- ion in the builder and move to scripter and do calculation the tool take it as neutral instead of oh- ion this  i verified through bader as well as mulliken analysis. So how I will put two ions charges one after the other like oh- ion on graphene and then say metal ion on this modeled sheet .

Dear Sir

I want to model graphene with hydroxyl group (oh-) and adsorb metal ion how the charge is being implemented on system means first i have to model the oh- ion then adsorb it on the sheet and then model metal ion and adsorb it on the oh- adsorbed sheet is it correct way of modelling the charged system or we need to put charges during optimization of the system.

if charges need to put during optimization of the system then what i need to do, should i need to put resultant charge on the system
for example: lets say
                                  charge on OH = -1 e
                                  charge on metal ion= +3e
    then for modelling metal ion adsorption on oh- adsorbed graphene, +2e should be given in the charge box in calculator to model metal ion adsorbed oh- adsorbed graphene

Thank you sir for your valuable reply but,

I have tried guassian but still it is mismatched.

so "Alternatively it could be that your k-point route used in the bandstructure does not contain the point where the minimal gap is located" for this what should i do. 

Dear Sir
I have computed the band structure and dos for gas adsorbed cu ion  decorated n doped graphene but it does not matches although i have varied my k points (increased) but it did not matches the band gap obtained in dos is smaller then the band gap obtained from band structure.

Thank you in advance

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