Topics

1

General Questions and Answers / DOS vs projected DOS

« on: September 18, 2020, 00:42 »

What is the difference between calculating DOS object vs projected DOS. I know projected DOS can give projections on orbitals, spin etc but the total DOS should be the same in both the cases. right? In my case, I get different value of DOS at fermi level if I read from DOS graph or from projected DOS.

2

General Questions and Answers / ampacity / current carrying capacity

« on: September 5, 2020, 01:07 »

How can I calculate the current carrying capacity/ ampacity using Quantum ATK?

3

General Questions and Answers / DOS vs PDOS

« on: July 14, 2020, 22:58 »

What is the difference between DOS and PDOS? Shouldn't the total DOS from PDOS analysis be equal to the one calculated using DOS analysis? I have  calculated DOS and PDOS for the same configuration and they are quite different.

4

General Questions and Answers / momentum resolved transmission spectrum

« on: July 3, 2020, 16:34 »

What information can be obtained by momentum resolved transmission spectrum of a material?
For instance, if it shows that at a certain energy, certain k points show high transmission, what does that physically mean?

5

General Questions and Answers / Unit Cell size

« on: July 1, 2020, 23:36 »

How to select the size of unit cell? I assume enough vacuum around the actual structure is needed. If my results change with change in size of unit cell, do I need to keep increasing the lattice parameters for convergence?

6

General Questions and Answers / moving geometry from labfloor to builder

« on: June 10, 2020, 00:18 »

I am using version 2019 and whenever I try to drag and drop a geometry from labfloor to builder I get a message that python has stopped working and the software closes. This issue was not there in previous versions and I could drag and drop geometries like this. I would really appreciate any help on how to overcome this issue.

7

General Questions and Answers / Orbital contributions in bandstructure

« on: June 6, 2020, 17:42 »

Is there a way to tell which orbitals are taking part to form a particular band in bandstructure?

8

General Questions and Answers / q dependent dielectric function

« on: May 7, 2020, 01:15 »

Hi is it possible to calculate q dependent dielectric function in quantum ATK as done in the paper
"Ab initio study of the dielectric response of crystalline ropes of metallic single-walled carbonnanotubes: Tube-diameter and helicity effects"?
They use Time dependent DFT. If I calculate optical spectrum in quantum ATK, is q value 0 by default?

9

General Questions and Answers / Transmission Spectrum for superconductors

« on: April 16, 2020, 18:34 »

What does the transmission spectrum for a superconductor look like? i.e if it is plotted for below its critical temperature. Does it show infinite transmission coefficient?

10

General Questions and Answers / Molecular Dynamics at low temperature

« on: April 16, 2020, 18:32 »

https://docs.quantumwise.com/casestudies/md_landauer/md_landauer.html

Can we use the method used in this tutorial to calculate transmission spectrum for low temperatures i.e close to 0K?

11

General Questions and Answers / Partial and projected DOS?

« on: April 2, 2020, 19:28 »

I want to know the difference between partial and projected DOS? In DOS analyzer we can select each atom and orbital to show DOS related to that particular atom and/or orbital. Is it the same as partial DOS?

12

General Questions and Answers / Negative Mulliken Population

« on: April 2, 2020, 16:41 »

Hello everyone

I need some information about what negative mulliken population means? Also in general how to calculate charge transfer from Mulliken population analysis?

13

General Questions and Answers / Isovalue

« on: March 23, 2020, 23:48 »

Hi

Can you please explain how to select isovalue for electron density visualization? and what does isovalue signify?
From what I understand electron density is a function of three spatial variables and hence a 3D sphere, each isovalue represents the surface of constant radius on that sphere. Please correct me if I am wrong here.

14

General Questions and Answers / Compare Data

« on: February 28, 2020, 21:12 »

While comparing two or more transmission spectra using 'compare data' it only shows the sum curve. Is there a way to compare transmission spectra of just spin up or spin down curves?

15

General Questions and Answers / Transmission Spectrum for unit cell vs device

« on: February 28, 2020, 17:52 »

https://docs.quantumatk.com/tutorials/transmission_gr_mos2/transmission_gr_mos2.html

The tutorial in this link says that transmission spectrum for a perfect periodic system  can be calculated from unit cell and detailed device setup is not required. Can I use this method to study the transmision spectrum of carbon nanotubes adsorbed with metal atoms?
Is the transmission given by this method is for an infinite tube and if I make a device that is for finite tube?