QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: shivgy on July 25, 2014, 14:27

Title: superlattice composed of graphene and MoS2
Post by: shivgy on July 25, 2014, 14:27
Respected sir,
While calculating bandstructure of graphene I am getting good result when following process is being followed :
Builder---> Add ---> database ---> graphene

but when i am adding more atoms to the graphene by using Bulk Tools ---> Supercell 4x4 or by using Bulk Tools ---> Repeat I am getting bad result (Straight Lines). can anyone please explain me what wrong I am doing?

I've tried DFT, and Extended Huckel; Exchange Correlation-- LDA and GGA

I want to simulate superlattice composed of graphene and monolayer MoS2

Reference: Structural and Electronic Properties of Superlattice Composed of Graphene and Monolayer MoS2
X. D. Li, S. Yu, S. Q. Wu, Y. H. Wen, S. Zhou, and Z. Z. Zhu
The Journal of Physical Chemistry C, 2013, 117, 15347 - 15353
Title: Re: superlattice composed of graphene and MoS2
Post by: zh on July 26, 2014, 03:50
The reason for your problem may be:   the setup of lattice for the 4x4 supercell is given by a customized way (see below), rather than the embedded Hexagonal() of Bravais lattices. So you can choose only "G, Z" in the Brillouin zone route in the "Band structure" analysis for the customized lattice.
# Set up lattice
vector_a = [4.9224, -8.52584689518, 0.0]*Angstrom
vector_b = [4.9224, 8.52584689518, 0.0]*Angstrom
vector_c = [0.0, 0.0, 6.709]*Angstrom
lattice = UnitCell(vector_a, vector_b, vector_c)

You can replace the above setup of lattice by "lattice = Hexagonal( a= 4.9224* 2 * Angstrom, c = 6.709 * Angstrom)". For the lattice defined by the embedded Hexagonal(), you can choose more  special k points for the  Brillouin zone route in the "Band structure" analysis.

Title: Re: superlattice composed of graphene and MoS2
Post by: shivgy on August 1, 2014, 07:13
Sir,

After interfacing the two hexagonal lattices and setting the matching parameter for minimum strain. The complete structure becomes unit cell. Setting it again for hexagonal lattice from BULK TOOLS--->LATTICE PARAMETER some part of the structure goes outside the box. is it okay ? can i proceed further for simulation? or I need to do something to bring the full structure inside the box.

please find the attached image file.
Thank you :)
Title: Re: superlattice composed of graphene and MoS2
Post by: Anders Blom on August 2, 2014, 07:58
Bulk tools>Wrap