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General Questions and Answers / Re: charge transfer
« on: April 14, 2017, 16:33 »
Dear Dr. Blom,
For band structure calculation does DFT-D2 has any impact?
For band structure calculation does DFT-D2 has any impact?
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General Questions and Answers / Re: charge transfer
« on: April 5, 2017, 16:23 »
Dear Dr. Blom,
Should I check "No SCF Iteration" to save computational time?
Should I check "No SCF Iteration" to save computational time?
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General Questions and Answers / Re: charge transfer
« on: April 3, 2017, 22:27 »
Dear Dr. Blom,
So, we dont have to use D2 for geometric optimization, right? or use D2 for final optimization.
So, we dont have to use D2 for geometric optimization, right? or use D2 for final optimization.
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Scripts, Tutorials and Applications / Graphene_MoS2 interface with electrode
« on: April 3, 2017, 22:20 »
I am trying to put graphene on the top of MoS2. Then, using device from bulk to add electrode. But, it was not letting me to do that. Following steps I followed,
1. Add graphene and MoS2 from database
2. Deleted one layer of MoS2
3. Graphene is on MoS2 using Interface tool and displacement tool is used to make the separation between them
4. Then structure was created and repeated to make it large
5. swap axes B<C and Y<Z
Please have a look into the attached python file.
1. Add graphene and MoS2 from database
2. Deleted one layer of MoS2
3. Graphene is on MoS2 using Interface tool and displacement tool is used to make the separation between them
4. Then structure was created and repeated to make it large
5. swap axes B<C and Y<Z
Please have a look into the attached python file.
5
General Questions and Answers / Re: charge transfer
« on: April 3, 2017, 17:45 »
Thank you Dr. Blom! Its working fine now. To save computational time what are the steps I could take.
1. Relax graphene while constraining SiO2 as fixed. Once graphene relaxed then optimize the whole structure again.
2. Should I use DFT-D2 for van der waals correction?
3. FFT2D for Poisson solver with C direction dirichlet instead of periodic?
4. Is there any influence by changing History steps? in Iteration Control.
1. Relax graphene while constraining SiO2 as fixed. Once graphene relaxed then optimize the whole structure again.
2. Should I use DFT-D2 for van der waals correction?
3. FFT2D for Poisson solver with C direction dirichlet instead of periodic?
4. Is there any influence by changing History steps? in Iteration Control.
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General Questions and Answers / Re: charge transfer
« on: April 3, 2017, 07:28 »
I was trying to build a structure like graphene on the top of SiO2 using interface tool. I have used displacement tool so that graphene layer could be 1.43 Angstrom away fromn SiO2 layer. I was getting following error consistently
** Back Engine Exception : Diagonalization error, overlap matrix not positive definite. This may be caused by atoms that are too close to each other or situated in equivalent positions, or a too low value of interaction_max_range. Check the configuration, basis set and/or try to increase the interaction_max_range.
** Location of Exception : eigensolutions.cpp:2091
Please advise me how to move graphene so that its 1.43 Angstrom away from SiO2 layer.
** Back Engine Exception : Diagonalization error, overlap matrix not positive definite. This may be caused by atoms that are too close to each other or situated in equivalent positions, or a too low value of interaction_max_range. Check the configuration, basis set and/or try to increase the interaction_max_range.
** Location of Exception : eigensolutions.cpp:2091
Please advise me how to move graphene so that its 1.43 Angstrom away from SiO2 layer.
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General Questions and Answers / Calculate Ion and Ioff values of GFET
« on: September 29, 2015, 18:58 »
Dear Dr. Blom,
How could I calculate Ion and Ioff values of GFET following the tutorial available in the web. Also, how could I plot drain-source (Vds) VS drain current?
How could I calculate Ion and Ioff values of GFET following the tutorial available in the web. Also, how could I plot drain-source (Vds) VS drain current?
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General Questions and Answers / Re: Transmission Spectrum of Graphene-Nickel Interface
« on: April 29, 2015, 00:08 »
Dear Mr. Umberto Martinez,
Please have a look.
Please have a look.
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General Questions and Answers / Re: Transmission Spectrum of Graphene-Nickel Interface
« on: April 27, 2015, 22:57 »
Dear Umberto Martinez,
Thank you. I tried the last configuration from the journal paper (from the figure-d section). I found out that whenever I am selecting C/Z (where the structure is periodic) as the width of the structure and transport direction, I couldn't convert the structure from bulk to device. I could do it when selecting B as the width and transport direction. Please help me if I can choose B as the transmission direction and how?
Thank you. I tried the last configuration from the journal paper (from the figure-d section). I found out that whenever I am selecting C/Z (where the structure is periodic) as the width of the structure and transport direction, I couldn't convert the structure from bulk to device. I could do it when selecting B as the width and transport direction. Please help me if I can choose B as the transmission direction and how?
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General Questions and Answers / Re: Transmission Spectrum of Graphene-Nickel Interface
« on: April 20, 2015, 23:50 »
Dear Mr. Umberto Martinez,
Thank you. Actually I was talking on how can I build zigzag edge graphene. Because by default the builder was giving me Armchair edge graphene only.
Thank you. Actually I was talking on how can I build zigzag edge graphene. Because by default the builder was giving me Armchair edge graphene only.
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General Questions and Answers / Re: Transmission Spectrum of Graphene-Nickel Interface
« on: April 19, 2015, 19:36 »
I was trying to follow the tutorial available in the website to grow graphene sheet (http://quantumwise.com/publications/tutorials/item/102-graphene-nickel-interface). By default it was giving me Armchair Graphene sheet using GUI. Is it possible to build Zigzag graphene sheet using GUI?
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General Questions and Answers / Re: Transmission Spectrum of Graphene-Nickel Interface
« on: March 26, 2015, 17:43 »
I am new with ATK and I dont know how to use scripting very well. I would appreciate your answer through GUI format or tell me how to use extended basis set in my code. Thank you
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General Questions and Answers / Transmission Spectrum of Graphene-Nickel Interface
« on: March 19, 2015, 02:20 »
I was trying to reproduce transmission spectrum from Kurt Stokbro et.al. I tried to optimize the structure geometry first then simulated for 401 k-point sampling. Exchange correlation LSDA and FFT as Poisson solver were used. But the thing was that transmission spectrum was not the same as the paper. Please help me on this topic.
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