Messages

1

General Questions and Answers / Inclusion of vdW in DFT

« on: August 20, 2016, 12:53 »

Dear ATK users
How to include vdW in DFT..Kindly help.



Thanks
Gagan

2

General Questions and Answers / Re: how to plot graphene phonon band structure having 18 atoms in unit cell

« on: July 6, 2016, 17:50 »

Thanks for the reply sir..But my problem is whether i am going accurately or not as i earlier written Suppose i want to prepare 50 atoms graphene sheet and study its phonons...I took 2 atoms from data base , repeated hexagonal unit cell in 4*4.. and for phonons i set 3*3*1 dynamical matrix....It will give me density matrix for 144 atoms..




alternatively i choose 8 atoms in unit cell(i dont know whether i should customize unit cell() instead of hexagonal for graphene or remain it hexa only which is default), and then set dynamical matrix for 5*5*1 which gives me matrix for 200 atoms...

my question is whether iam getting phonons for 144/200 atoms of graphene sheet or 32 atom/ 8 atoms in both cases respectively..


Thanks in anticipation
 

3

General Questions and Answers / Re: how to plot graphene phonon band structure having 18 atoms in unit cell

« on: July 3, 2016, 21:00 »

Dear Dr Blom
I want to calculate Phonon band structure for 18/32 atom graphene sheet and then adsorb it by some metal (1/18 or 1/32 )and see the changes

4

General Questions and Answers / Re: how to plot graphene phonon band structure having 18 atoms in unit cell

« on: July 3, 2016, 20:46 »

#reply 6 Thanks for the reply but can you please elaborate it

5

General Questions and Answers / Re: how to plot graphene phonon band structure having 18 atoms in unit cell

« on: July 1, 2016, 09:47 »

I created 3*3 supercell from database using 7*7*1  k-points using ATK-DFT and hexagonal unit cell....i opimized the sheet first..then dragging the minimized sheet in script,i added phonon bandstructures from analysis..then changed k-sampling to 111 in each direction and 3*3*1 in dynamical matrix..and 200 segment in phonon bandstructures and brillioun zone to Gamma, M, K, G....is it ok?or should i change it to ATK-classical and use Brenner or Tersoff

6

General Questions and Answers / Re: how to plot graphene phonon band structure having 18 atoms in unit cell

« on: July 1, 2016, 09:18 »

How to use  the Brillouin zone folding in ATK...Tutorials are for 2 atoms in unit cell of graphene not for 18 atom or 32 atom sheet..

7

General Questions and Answers / how to plot graphene phonon band structure having 18 atoms in unit cell

« on: June 30, 2016, 20:29 »

I want to ask do you have any idea about Graphene Phonon bandstructures.I have plotted for graphene with two atoms in basis cell..I want to plot for 3*3 sheet of graphene..How to plot in ATK..unable to understand in latest manual too or how to choose density matrix..Kindly help..it is written in manual

The dynamical matrix is calculated using the finite difference method in a repeated cell, which is sometimes also referred to as frozen phonon- or super-cell method.

How to pursue further

8

General Questions and Answers / how to write q sampling points in phonon density of states in graphene.

« on: June 20, 2016, 20:35 »

Hi
can anybody guide me how to plot Phonon density of states in graphene as well as phonon band structure

9

General Questions and Answers / how to build graphene sheet

« on: June 19, 2016, 20:56 »

Hi i am new to ATK...just wanted to know How to build graphene sheet..If i select bulid>ADD>from database>select graphene>supercell.

Or
Add>from pluggins>nanosheet then repeat d supercell...Whats d difference between the two