Topics

1

General Questions and Answers / Regarding bandstructure difference between unit cell and repeated cell

« on: September 1, 2020, 11:11 »

Dear sir, I have calculated the bandstructure of unit cell and its repeated cell the bandstructure of both the system are different. I have calculated the bandstructure of unit cell for brillioun zone point X, Z T, Y, G which is in well agreement with reference literature 10.1016/j.physb.2018.02.015. but when I have repeated the cell than the bandstructure is not sane as unit cell. I have tried all possible brillioun zone point. But the bandstructure is not matched. Please help me out
Related Log files and py files are attached
Thanks in advance
Sonal

2

General Questions and Answers / Basis set superposition error correction

« on: August 31, 2020, 14:36 »

Dear sir,
Is basis set superposition error correction i.e. counterpoise correction is necessary in sensing of molecules on a sheet. is this error cause large variation from the experimental results as given in the manual of counterpoise correction or we may consider only vanderwall interaction and ignore counterpoise correction.

3

General Questions and Answers / Calculation of doping concentration

« on: August 9, 2020, 10:17 »

Dear sir,
When we doped the nanoribbons then in the calculation of doping concentration we should take hydrogen atom into account or not?? Is the hydrogen atoms are only for avoiding the dangling bond or we should considered the concentration of hydrogen atoms while calculating the concentration.

4

General Questions and Answers / Differene between zero bias conductance in bulk mode and device mode

« on: May 13, 2020, 12:51 »

Dear sir,
I have calculated Zero bias conductance of graphene nanosheet in bulk mode and in device mode there is huge difference between conductance. Can you please tell me why this difference is appearing in conductances.


Please help me out
Thanks in advance

5

General Questions and Answers / Brillouin zone in bandstructure of graphene nanosheet

« on: May 13, 2020, 12:42 »

Dear sir,
I have build a graphene nanosheet in ATK-VNL,  when I am calculating the band structure of nanosheet than the Brillouin zone point appear by default are only G, Z and bandstructure having bandgap of 0.02eV.  While In the hexagonal graphene sheet dirac cone with zero band gap is present at K point of brillouin zone but in the nanosheet which build from builder directly. I have explored the literature and have not found any paper which reported the electronic properties of retangular nanosheet.
1. Is there any difference in electronic properties of the hexagonal and unit cell or rectangular  shaped graphene sheet are they dependent on the supercell or i did something wrong.
2. brillouin zone point G, Z are for one dimensional material or it can also be used for Two dimensional material. I mean from the bandstructure how can we identify that this is the bandstructure of two-dimensional material or one dimensional material in case of unit cell.
For example graphene nanoribbon and nanosheet both have brillouin zoner point G, Z how can we differentiate both bandstructure.


Thanks in Advance

6

General Questions and Answers / errore in device optimization by extended huckle

« on: October 22, 2019, 14:41 »

Dear sir, I am facing issue in device optimization by extended huckle. there was an erroe msg that no pair potential are given. and also shows error in python file in optimization by LBFGS optimizer. is LBFGS optimizer is not supported by extended huckle or there is any error in my softwares potential files.

7

General Questions and Answers / how to build phospherene nanoribbon in atkvnl with hydrogen passiviated edge

« on: September 28, 2019, 06:15 »

Dear sir, I am facing issue with the builder in building phosphorene nanoribbon with hydrogen passivated edge, when I built phosphorene nanoribbon in 2016.03 version with builder plugin tool I have got all phosphorous hydrogen passivated. after deleting all hydrogens  except at edges and  after introducing buckling we have optimized the structure. Further that after the optimization we found that the geometry is not proper it is breaked. sir please help me out from this problem. I want to build blue and black phosphorene nanoribbon. 



Thanks

8

General Questions and Answers / how to identify that which point should be used for calculating fermi velocity

« on: April 25, 2019, 14:33 »

sir, i want to know that how to identify which point G or Z should be considered for calculating fermi velocity when there is a band gap in silicene and germanene nanoribbon and in case of zero band gap which band index is considered for calculating Fermi velocity. In tutorial https://docs.quantumwise.com/manuals/Types/calculateVelocity/calculateVelocity.html  you have considered band index 3 but at dirac point there is band 3 and band 4 also i an little bit confused about this
please help me out.


Thanks