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General Questions and Answers / Re: optical spectrum
« on: July 28, 2014, 22:19 »
I have been doing the simulations using mgga only.... .
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General Questions and Answers / optical spectrum
« on: July 28, 2014, 12:38 »
I am trying to calculate the value of dielectric constant for black phosphorous as per the publication
However the values are not matching with that of the reported ones. (along c=12.5, along a=10.2 and along b=8.3).
Though the dielectric constant value along c axis is more or less close to that reported in the paper the values along other two directions are far apart. Change in the the 'k grid points' and the 'bands above and below Fermi level' were done, still there was no match.
Please help.
However the values are not matching with that of the reported ones. (along c=12.5, along a=10.2 and along b=8.3).
Though the dielectric constant value along c axis is more or less close to that reported in the paper the values along other two directions are far apart. Change in the the 'k grid points' and the 'bands above and below Fermi level' were done, still there was no match.
Please help.
3
General Questions and Answers / Re: Strain after optimization
« on: March 26, 2014, 18:49 »
While building the interface using the interface builder I have chosen to strain the second surface only. After this , I have put the entire structure for geometry optimization. What I am actually interested to know is, how the interface strain on the second surface gets changed after geometry optimization, not the stress of the entire system. Kindly suggest a way.
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General Questions and Answers / Re: Strain after optimization
« on: March 24, 2014, 12:53 »
Can you please explain which are the corresponding faces for the elements given in the stress report. I saw the link but I could not figure out from it. Please explain in details.
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General Questions and Answers / Re: Strain after optimization
« on: March 24, 2014, 08:04 »
I went through the tutorial and inserted the necessary command n the script file. The stress report printed in the log file is shown here
Stress Report |
+------------------------------------------------------------------------------+
| [[ -1.81118773e-02 3.92228089e-06 -4.73882461e-07] |
| [ 3.92228089e-06 -2.01589654e-02 5.15914664e-07] |
| [ -4.73882461e-07 5.15914664e-07 -7.64831780e-04]] eV/Ang**3 |
+---------------------------------------
Can you please explain about the different elements in this matrix and what they denote.
Stress Report |
+------------------------------------------------------------------------------+
| [[ -1.81118773e-02 3.92228089e-06 -4.73882461e-07] |
| [ 3.92228089e-06 -2.01589654e-02 5.15914664e-07] |
| [ -4.73882461e-07 5.15914664e-07 -7.64831780e-04]] eV/Ang**3 |
+---------------------------------------
Can you please explain about the different elements in this matrix and what they denote.
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General Questions and Answers / Strain after optimization
« on: March 17, 2014, 16:48 »
Sir,
When we make an interface using the interface builder a strain is applied onto one of the surfaces. After that the structure is optimized. I would like to know if there is a change in the distribution of strain and its magnitude after geometry optimisation of the structure.
When we make an interface using the interface builder a strain is applied onto one of the surfaces. After that the structure is optimized. I would like to know if there is a change in the distribution of strain and its magnitude after geometry optimisation of the structure.
7
General Questions and Answers / Re: MoS2/Al2O3
« on: March 14, 2014, 08:19 »
Thank you for the reply. It was really helpful 
. I would like to know
1. whether it is possible to get stoichiometric Al/O atoms in the Al2O3 arrangement inside the supercell, beause the moment I make an interface the arrangement of Al2O3 gets changed leading to nonstoichiometric Al/O atoms at the top layer.
2. And if there is any way to remove the surface states due to nonstoichiometric topmost Al/O layers. I have checked by increasing the vacuum space but there was no change in band structure
.
. I would like to know 1. whether it is possible to get stoichiometric Al/O atoms in the Al2O3 arrangement inside the supercell, beause the moment I make an interface the arrangement of Al2O3 gets changed leading to nonstoichiometric Al/O atoms at the top layer.
2. And if there is any way to remove the surface states due to nonstoichiometric topmost Al/O layers. I have checked by increasing the vacuum space but there was no change in band structure
.
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General Questions and Answers / Re: MoS2/Al2O3
« on: March 4, 2014, 10:14 »
I had already passivated the Al2O3 structure and then run the simulation and obtained the band structure with fermi level crossings. Another thing that I have observed is that , the band structure of this super cell keeping only the Al2O3 slab within it , is not producing the result as it should for an insulator. However the band structure for simple bulk Al2O3(cleaved along 0001) is showing a bandgap of ~5eV. Is there something wrong in super cell formation or some problem in the method of interface formation or something else. Please suggest.
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General Questions and Answers / MoS2/Al2O3
« on: March 4, 2014, 06:42 »
Dear Sir,
I am trying to simulate band structure of monolayer MoS2 on Al2O3(cleaved along 0001). The problem is that the band structure of the system is not coming correctly. The bands are crossing the Fermi level, but we expect the system band structure to be similar to that of monolayer MoS2. However the band structure of bulk Al2O3(0001) is coming correct. Using the bulk passivated Al2O3(0001) I have created an interface with monolayer MoS2 and changed it to hexagonal super cell and then simulated this super cell to get the system band structure. Please suggest what the error can be.
I am trying to simulate band structure of monolayer MoS2 on Al2O3(cleaved along 0001). The problem is that the band structure of the system is not coming correctly. The bands are crossing the Fermi level, but we expect the system band structure to be similar to that of monolayer MoS2. However the band structure of bulk Al2O3(0001) is coming correct. Using the bulk passivated Al2O3(0001) I have created an interface with monolayer MoS2 and changed it to hexagonal super cell and then simulated this super cell to get the system band structure. Please suggest what the error can be.
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