Recent Posts

1

Questions and Answers / Re: Analysis for finding out the Hybridization state ?

« Last post by Nayab Shiraz on August 11, 2020, 17:19 »

Hi can you please elaborate how we can get hybridization information from mulliken population prjected on bonds?

2

Questions and Answers / Re: LCAO basis set used for initialisation and projection in PlaneWave caclulator

« Last post by Nordland on August 11, 2020, 08:44 »

Hi hsuya,

An DFT code (LCAO or Plane-Wave) need a initial guess for the electron density. The plane wave code uses LCAO orbitals to create a starting density for the self-consistent loop. This is what is meant by initialiation.

In addition, some post-analysis of the self-consistent state requires a projection onto atomic orbitals, and here the LCAO orbtials are used again.

3

Questions and Answers / Re: I need to have albumin molecule on ATK

« Last post by mlee on August 11, 2020, 08:34 »

You can build it using the molecular builder. Or you can add from file using the extension .cif format in the builder.

4

Questions and Answers / Problem regarding Monolayer BP Double Gate MOSFET IV characterestics

« Last post by mashru on August 10, 2020, 16:59 »

Hi,

I am trying to simulate a Black phosphorus channel double gate junctionless mosfet. For junctionless mosfet S/D and channel have the same doping concentration. So based on the concept of junctionless mosfet i considered the same doping concentration whole through the device. Unfortunately i am getting the iv curve which is not showing the any on off behaviour also i have some confusion between TCAD and Atomistic simulation.

Here are the specs of  device and parameters i used
Gate length = 6nm
Doping =1e14
Gate Metal = OV (for both gate metals)
Density Mesh cutoff =100 Hartree
K-point sampling (c-direction) =200
Gate voltage = -0.5 to 0V
Drain Voltage = 0.05V
Poisson solver= PCG and Neuman boundary condition in A direction and Periodic in B direction
Device Algorithm = Greens function is used with recursion sellf energy calculator

When i try to dope the channel region with the doping widget, it shows that channel region corresponds to left electrode

So please help me out about this problem whether i am making any mistake and also in TCAD we usually define workfunction of metal gate explicitly but in QuantumATK do i need to explicitly declare the gate metal workfunction or it will calculate the WF for a specific applied bias.

For the convenience i am attaching the log file of the simulation and alos the py file and screenshots of some of the settings.

5

Questions and Answers / Re: Periodic Boundary Conditions

« Last post by Petr Khomyakov on August 10, 2020, 14:11 »

To avoid using periodic boundary conditions, you may adopt Dirichlet-Dirichlet (or Neumann-Neumann) boundary conditions in the out-of-plane z-direction, or mixed Dirichlet-Neumann boundary conditions if the 2D system of study is asymmetric (no mirror symmetry) in z-direction. In this case, one may avoid an artificial dipole formation due to this asymmetry.

6

Questions and Answers / Re: Calculation of doping concentration

« Last post by Petr Khomyakov on August 10, 2020, 13:58 »

In principle, it is up to you. I would probably avoid doping hydrogen atoms used for passivation of nanoribbon edges, as it looks a bit artificial.

7

Questions and Answers / Re: Adding DFT-D2 in planewave calculators

« Last post by Petr Khomyakov on August 10, 2020, 13:51 »

This feature for using Grimme's correction in the PW calculator will become available in the coming release of QuantumATK.

8

Questions and Answers / Re: optical spectrum

« Last post by Roc2019 on August 9, 2020, 10:56 »

Thank you Dr. Gunst   

9

Questions and Answers / Calculation of doping concentration

« Last post by sonal AGRAWAL 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.

10

Questions and Answers / LCAO basis set used for initialisation and projection in PlaneWave caclulator

« Last post by hsuya on August 9, 2020, 03:12 »

I am using plane wave calculator for optimising my structure but in Pseudopotential->Basis Set in the plane wave calculator it is showing  "The LCAO basis set is used for initialization and projection". Why is it so, shouldn't it be plane wave basis set instead? I have attached a screenshot for the same.