Topics

1

General Questions and Answers / Problem in introduce Force convergence, Vacuum and setting camera

« on: September 10, 2021, 18:59 »

Sir, sorry to disturb you. Can you please explain me how to introduce and set this :-

1) All the atoms in considered geometries are fully relaxed to change their individual position until the force convergence criteria of 0.05 eV/A is achieved.

2) In order to avoid any Columbic interaction between the periodic images of ribbon in the transverse directions, a large vacuum space of 10A is considered.

3) How to setting the camera and swap axes to get into this example direction (attached). I only managed to get z and y-axis right.

Im currently studying about BNNR. I really appreciate if anyone can tell me this. Thankyou

2

General Questions and Answers / Z-BNNR Bandstructure

« on: September 7, 2021, 18:33 »

Hi Sir,

Im currently studying Z-BNNR from this paper "Band Gap Engineering by Carbon doping in Boron Nitride Nanoribbons: First Principle study by Satyendra Singh Chauhan, Shobhna Ferwani".

The attachment files below are the results of Z-BNNR pristine that I tried to follow and study like the one in the paper.  I think i have followed the method steps shown in the paper. Sadly, I didnt get the same bandstructure of pristine Z-BNNR as in paper. Am i missing some importance steps ?

Also I have another question, Sir. What are actually the best calculator for BNNR ?

Sir, Im appreciate if you can guide and advise me what should i do next. Thankyou so much

3

General Questions and Answers / The setting of Interatomic

« on: September 2, 2021, 01:23 »

Hi,

Is there any setting to determine whether the interatomic to form chemical bonding or not ?
Thankyou.

4

General Questions and Answers / How to get the range of x-axis from the bandstructure ?

« on: September 1, 2021, 08:44 »

Hi everyone,

I have a question about how to get the range of x-axis from the bandstructure ?
Below i have attached the image of bandstructure. Thankyou

5

General Questions and Answers / CNT Schottky diode

« on: August 11, 2021, 21:26 »

Hi Sir,

Im currently studying CNT schottky diode from this paper "A Comprehensive Atomic Study of Carbon Nanotube Schottky Diode Using First Principles Approach Ping Bai,   Kai Tak Lam,   Erping Li ,  Chang, K.K .

I have successfully build the cnt structure and Al atoms separately. Then i created the interface between cnt and Al through interface builder under builders section. However, the structure doesnt look right.  I also tried to merge it  through merge cells under bulk tools section, to see if i can solve. But the structure is still wrong. Therefore, my question is how to get the device of cnt schottky diode like the one in the paper. How can i make it overlap on the left electrode?
I really hope someone can help and advice me what should i do next. Thank you so much.

6

General Questions and Answers / Questions about Initial state and Ferromagnetic

« on: March 8, 2020, 08:53 »

Hi Sir,

Currently, I'm studying graphene (AGNR)  based spin logic gates. Im using this paper as a guide for me, here is the link https://doi.org/10.1063/1.3562320 . I know i want to study AGNR, but since the paper is using ZGNR, i also want to know ZGNR. Thefore, i have a few questions to ask. Please i really need your help and guidance 

1. To set the magnetization, i need to set it using Initial state right? I have been followed these two tutorials
https://docs.quantumatk.com/tutorials/fe_mgo_fe/fe_mgo_fe.html  and https://docs.quantumatk.com/tutorials/transmission_atomic_chain/transmission_atomic_chain.html.

Right now, im focusing to get the NOT logic gate first. To get NOT logic gate, i need to set the magnetic configuration to [1,0] where the magnetization of left electrode is set to 1 and right electrode is set to 0 (non-magnetic). Both electrodes contain elements of carbon and hydrogen.I have tried it, but i didnt get the same results like the paper have obtained.

This is some of the scripts i have done;

# -------------------------------------------------------------
# Two-probe Configuration
# -------------------------------------------------------------

# -------------------------------------------------------------
# Left Electrode
# -------------------------------------------------------------

# Set up lattice
vector_a = [10.0, 0.0, 0.0]*Angstrom
vector_b = [0.0, 17.1043, 0.0]*Angstrom
vector_c = [0.0, 0.0, 4.92200342]*Angstrom
left_electrode_lattice = UnitCell(vector_a, vector_b, vector_c)

# Define elements
left_electrode_elements = [Hydrogen, Carbon, Carbon, Carbon, Carbon, Hydrogen, Carbon, Carbon,
                           Carbon, Carbon, Hydrogen, Carbon, Carbon, Carbon, Carbon, Hydrogen,
                           Carbon, Carbon, Carbon, Carbon]


# -------------------------------------------------------------
# Initial State
# -------------------------------------------------------------
initial_spin = InitialSpin(scaled_spins=[1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0])
device_configuration.setCalculator(
    calculator,
    initial_spin=initial_spin,


2. Next, do i need to setup ferromagnetic configuration? Since I'm using fully ZGNR where the elements are only carbon and hydrogen. 
Due to this info https://www.doitpoms.ac.uk/tlplib/ferromagnetic/printall.php, the periodic table shows both carbon and hydrogen are diamagnetic.
 
In this paper https://doi.org/10.1063/1.3562320 , it didn't mention anything about ferromagnetic.


I hope someone can reply this and help me.

7

General Questions and Answers / The different

« on: February 22, 2020, 10:20 »

Hi Sir,

I am very confused. What is the different or relation between magnetic configurations (like one is magnetized while other is non-magnetic) and conventional parallel/anti-parallel  magnetic configurations of GMR devices ?

8

General Questions and Answers / How to set the magnetization of the electrodes ?

« on: November 21, 2019, 06:03 »

Dear sir,

Im a newbie to Quantum ATK. I want to study on graphene (AGNR) based logic gates. I have difficulties to understand on how to set magnetization of the electrodes and where to set it in Quantum ATK. I want to set magnetization of left electrode to -1 (magnetized) and right electrode is set to 0 (non-magnetic).

9

General Questions and Answers / Graphene (spintronic).

« on: October 31, 2019, 09:31 »

Hi, i want to do graphene based spin logic gate. How do i set the spin up & spin down ? Could you help me out