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General Questions and Answers / Re: Spin Orbit Coupling
« on: March 3, 2016, 16:41 »
Thank you very much for the recommendations, Dr. Blom!
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General Questions and Answers / Re: Spin Orbit Coupling
« on: March 3, 2016, 15:12 »
Doing calculations with FHI pseudopotential and MGGA method, I get the correct result. Once I change the OMX potential for the SOC calculation, the conduction and valence band get together. Zooming a lot, there is a small gap but it measures 0.0002 eV.
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General Questions and Answers / Re: Spin Orbit Coupling
« on: March 3, 2016, 14:54 »
Hello!
I did calculations for the SOC for InSb(semiconductor). I got great bandstructure results with MGGA but once I changed the pseudopotential to the OMX, I get a closed bandstructure. I did all recommendations on the cut-off parameter and the K points. Also tried some other parameters to see if it changed. Is there another pseudopotential that can be used for the SOC calculation besides that one? Also, any other recommendation would be very helpful.
Thank you!
Juan
I did calculations for the SOC for InSb(semiconductor). I got great bandstructure results with MGGA but once I changed the pseudopotential to the OMX, I get a closed bandstructure. I did all recommendations on the cut-off parameter and the K points. Also tried some other parameters to see if it changed. Is there another pseudopotential that can be used for the SOC calculation besides that one? Also, any other recommendation would be very helpful.
Thank you!
Juan
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General Questions and Answers / Re: Spin Orbit Coupling
« on: February 29, 2016, 15:18 »
I thank you very much for the quick reply and information! 
Juan
Juan
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General Questions and Answers / Spin Orbit Coupling
« on: February 29, 2016, 14:12 »
Dear All,
I'm studying a semiconductor (InSb) and need to do calculations on spin orbit coupling. In the tutorial "Noncollinear calculations for metallic nanowires" you give some parameter on calculations for Nickel and pre-calculations for the convergence of values. Are those parameters more or less good approximation to start a calculation on SOC for a semiconductor? I've been looking for information but don't find just a few papers. If you know a good reference or references for this, can you please let me know? Thank you.
Sincerely
Juan
I'm studying a semiconductor (InSb) and need to do calculations on spin orbit coupling. In the tutorial "Noncollinear calculations for metallic nanowires" you give some parameter on calculations for Nickel and pre-calculations for the convergence of values. Are those parameters more or less good approximation to start a calculation on SOC for a semiconductor? I've been looking for information but don't find just a few papers. If you know a good reference or references for this, can you please let me know? Thank you.
Sincerely
Juan
6
General Questions and Answers / Body Centered Tetragonal Brillouin Points
« on: December 21, 2015, 18:43 »
Dear all,
I'm investigating about the Weyl semimetal. It is a body-centered tetragonal structure. The Brillouin zone on papers is: G, sigma, N, sigma1, Z, G, X. The program just provides G, N and X. I don't know the Z, sigma and sigma1 coordinates. Can you please tell me where I can find the points for these or if you be so kind to provide them? Thank you!
Sincerely
Juan
I'm investigating about the Weyl semimetal. It is a body-centered tetragonal structure. The Brillouin zone on papers is: G, sigma, N, sigma1, Z, G, X. The program just provides G, N and X. I don't know the Z, sigma and sigma1 coordinates. Can you please tell me where I can find the points for these or if you be so kind to provide them? Thank you!
Sincerely
Juan
7
General Questions and Answers / Phase Transition in Materials
« on: September 28, 2015, 17:46 »
Dear all,
I'm studying the BaTiO3 material. Right now, I'm trying to replicate the phase transition from tetragonal (room temperature) to cubic (aprox. 393 K). Using MD, I'm using the ATK-Classical with the parameter set Pedone_2006Fe3 (it also provides the F2). The additional info says that the Brenner and EMT calculators don't have parameters for Barium (same additional info for all the parameters set). I'm using the NVT Berendsen type of MD with the recommended parameters in the tutorial. My questions are:
-If the parameter set I'm using does not have information on the parameters of one of the atoms in my structure, will this affect the results on the calculations? (Lets say Total Energy)
-Is it adequate to use the ATK-DFT calculator using molecular dynamics? I tried using it (just putting the calculator and leaving it with default parameters) but the program was still running after five days! I know some calculations are long but I am not sure if this combination can have something to do with this prolonged time(I'm using a fast machine for this type of calculations). I ran the calculation with the ATK-Classical and it not took so much time.
-I know if there is a change in total energy, there may be a phase change. I would like to know how can I make a graph of TotalEnergy(Temperature). I looked for this in the forum but the only things I found were the ones you provide in the MD tutorial (V(t) and P(t) for the NPT Melchionna) and for the Langevin type, you use the following script:
# Get the kinetic energies
kinetic_energies = md_trajectory.kineticEnergies()
# The number of constrained atoms
number_of_constraints = 10
# Calculate the degrees of freedom in the system
degrees_of_freedom = bulk_configuration.numberOfAtoms() - number_of_constraints
# Calculate the temperatures from the kinetic energies
temperatures = [ke/(1.5*degrees_of_freedom)/boltzmann_constant for ke in kinetic_energies]
I don't know if this can be used for my purpose.
I eagerly wait for your response.
Regards
Juan
I'm studying the BaTiO3 material. Right now, I'm trying to replicate the phase transition from tetragonal (room temperature) to cubic (aprox. 393 K). Using MD, I'm using the ATK-Classical with the parameter set Pedone_2006Fe3 (it also provides the F2). The additional info says that the Brenner and EMT calculators don't have parameters for Barium (same additional info for all the parameters set). I'm using the NVT Berendsen type of MD with the recommended parameters in the tutorial. My questions are:
-If the parameter set I'm using does not have information on the parameters of one of the atoms in my structure, will this affect the results on the calculations? (Lets say Total Energy)
-Is it adequate to use the ATK-DFT calculator using molecular dynamics? I tried using it (just putting the calculator and leaving it with default parameters) but the program was still running after five days! I know some calculations are long but I am not sure if this combination can have something to do with this prolonged time(I'm using a fast machine for this type of calculations). I ran the calculation with the ATK-Classical and it not took so much time.
-I know if there is a change in total energy, there may be a phase change. I would like to know how can I make a graph of TotalEnergy(Temperature). I looked for this in the forum but the only things I found were the ones you provide in the MD tutorial (V(t) and P(t) for the NPT Melchionna) and for the Langevin type, you use the following script:
# Get the kinetic energies
kinetic_energies = md_trajectory.kineticEnergies()
# The number of constrained atoms
number_of_constraints = 10
# Calculate the degrees of freedom in the system
degrees_of_freedom = bulk_configuration.numberOfAtoms() - number_of_constraints
# Calculate the temperatures from the kinetic energies
temperatures = [ke/(1.5*degrees_of_freedom)/boltzmann_constant for ke in kinetic_energies]
I don't know if this can be used for my purpose.
I eagerly wait for your response.
Regards
Juan
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General Questions and Answers / Re: Bandstructure does not show
« on: September 3, 2015, 15:51 »
Hey!
I just wanted to say thanks for the recommendations. I actually ran the optimizations on my computer and there was no problem. I can see the bandstructure. My computer has 14.2 version, same as the cluster. I don't think it was the version difference. Although, as Blom says, probably I was overriding some file without me knowing about. Again, thank you very much!
Best Regards
I just wanted to say thanks for the recommendations. I actually ran the optimizations on my computer and there was no problem. I can see the bandstructure. My computer has 14.2 version, same as the cluster. I don't think it was the version difference. Although, as Blom says, probably I was overriding some file without me knowing about. Again, thank you very much!
Best Regards
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General Questions and Answers / Re: Bandstructure does not show
« on: August 25, 2015, 18:44 »
Hello!
I ran the calculations once more. I did it for the BiFeO3 Rhombohedral structure (no optimization) and with optimization (Optimized1 and Optimized2) of 0.001 eV/A and 0.05 eV/A respectively. Again, the same problem appears. I'm trying to upload the .nc files but they are large and the post won't let me. The one I'm interested in is the Optimized1. Was the first one to show me the error message. If there is other way to let you have the .nc files, let me know. I'll wait for your response. Thank you!
I ran the calculations once more. I did it for the BiFeO3 Rhombohedral structure (no optimization) and with optimization (Optimized1 and Optimized2) of 0.001 eV/A and 0.05 eV/A respectively. Again, the same problem appears. I'm trying to upload the .nc files but they are large and the post won't let me. The one I'm interested in is the Optimized1. Was the first one to show me the error message. If there is other way to let you have the .nc files, let me know. I'll wait for your response. Thank you!
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General Questions and Answers / Re: Bandstructure does not show
« on: August 21, 2015, 14:47 »
Thank you, Wellendorff, for the help! I'll download the update and see if that works.
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General Questions and Answers / Re: Bandstructure does not show
« on: August 20, 2015, 14:38 »
To upgrade, I download again the program from the page, right? I think there should be an "upgrade" option at the top bar in the LabFloor.
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General Questions and Answers / Re: Bandstructure does not show
« on: August 19, 2015, 22:56 »
I followed your recommendation about first doing the optimization and then calculating the bandstructure for the optimized rhombohedral structure of BFO. The program finishes but I still get the same error. I really don't know what could the problem be. I've been thinking if it has to do with the displacement of the atoms after the optimization?
Thanks
Thanks
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General Questions and Answers / Re: Bandstructure does not show
« on: August 19, 2015, 17:20 »
Thank you very much. Anyhow, I still need to check on that because I need to run more calculations. If it ran without problem, probably I'm missing something either a plugin or something is going on when I translate the file from the server to the computer. I really appreciate the help!
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General Questions and Answers / Re: Bandstructure does not show
« on: August 19, 2015, 15:40 »
No, I did not do the recalculation after the optimization. I'll do that right now.
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General Questions and Answers / Re: Bandstructure does not show
« on: August 18, 2015, 18:19 »
Yes, it is on the LabFloor. Yes, I unchecked the old calculation and still appears the same error.
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