1. 2D Materials design Thomas Archer and Stefano Sanvito
IMRA, CRANN TCD May 2016
2D Materials design
Thomas Archer and Stefano Sanvito
School of Physics and CRANN, Trinity College Dublin, IRELAND

2. Research tasks from the introductory meeting on the 24th April
TCD to build up a library of 2D materials bulk
TCD to build up a library of 2D materials monolayers

3. Database setup Domain setup www.2d.materials-mine.com
Password protected
Username/Password: IMRA/IMRA
Mysql database backend stores basic information
Lattice parameters, Enthalpy of formation, COD database number ...
Flat file storage for DOS files

4. Automation of Workflow
Key:
In progress
Implemented
No work required
CIF file
Web interface
2d.materials-mine.com
Find primitive cell
Create geomitry.in file for FHI-AIMS
FHI-AIMS parameters:
Tight basis, force and energy tolerance, K-grid
Automated job management: GOLUM
Raw data archived
Selected quantities extracted

5. Selected simulation parameters
FHI-AIMS all electron DFT implementation
Tkatchenko and Scheffler vdw functional on top of pbe
Tight basis
Adaptive K-point mesh maintaining a constant accuracy
Force tolerance 10^-4ev/Ang
Electronic convergence default "tight" parameters
Spin-polarized calculations in FM phase

6. Elemental database http://2d.materials-mine.com/

7. Elemental database http://2d.materials-mine.com/
2D and AB stacked databases are empty at present, this is in progress

8. 2D Materials design 20th May 2016 Thomas Archer and Stefano Sanvito
IMRA, CRANN TCD April 2016
2D Materials design
20th May 2016
Thomas Archer and Stefano Sanvito
School of Physics and CRANN, Trinity College Dublin, IRELAND

9. Research tasks from the introductory meeting on the 24th April
1) calculation of bulk crystal parameters (of MX compounds of our list of 2D crystals)
2) calculation of 2D crystal parameters (of MX compounds of our list of 2D crystals)
3) then bilayers can start
Point 1 and 2 should be completed within the next 2-3 weeks.

10. Database setup (again just for reference)
Domain setup
Password protected
Username/Password: IMRA/IMRA
Mysql database backend stores basic information
Lattice parameters, Enthalpy of formation, COD database number ...
Flat file storage for DOS files

11. Automation of FHI-AIMS calculations
All electron – highest accuracy DFT code
Computationally effect
VdW implementation
Premade defaults make selection of appropriate parameters easy
However, convergence is vey sensitive to the initial spin configuration.
Teach the algorithm how to deal with the issue
Solve a convergence issue

12. Elemental database http://2d.materials-mine.com/
Automatic job summation not online yet. Due to convergence issues

13. Elemental database http://2d.materials-mine.com/
Plotting script implemented from the database
All ground state elemental phases calculated. Except a few exotic elements.

14. 2D bulk and monolayers http://2d.materials-mine.com/
Listed 2D materialscalculated in their
bulk phase and
monolayers
Symmetry
analysis of
relaxed structure
Integrative DOS plotting

15. AB stacked layers
AB stacked layers
Lattice match through strain
Large super cell
Empirical/model approach
Inherent
structures
Need to identify
suitable modeling techniques
Inexpensive to
calculate.
We can try
many possibilities
Affect of strain is unknown
Scaling of DFT limits the number of systems we can do

16. Construction of the heterostructures
1) Stack polymorphism
ACS Nano 4, 3690 (2014)

17. Construction of the heterostructures
1) Stack polymorphism
ACS Nano 4, 3690 (2014)

18. Construction of the heterostructures
1) Stack polymorphism
ACS Nano 4, 3690 (2014)

19. Construction of the heterostructures
1) Stack polymorphism
ACS Nano 4, 3690 (2014)

20. Construction of the heterostructures
2) Inherent heterostructures 2H
1Tn
J. Phys. Chem. C 120, 8927 (2016)

21. Construction of the heterostructures
2) Inherent heterostructures
J. Phys. Chem. C 120, 8927 (2016)

22. Construction of the heterostructures
3) Poorly commensurate structures
J. Phys. Chem. C XXX, XXX (2016)

23. Construction of the heterostructures
3) Poorly commensurate structures
J. Phys. Chem. C XXX, XXX (2016)

24. Construction of the heterostructures
3) Poorly commensurate structures
J. Phys. Chem. C XXX, XXX (2016)

25. Continuation of the project
Database of agreed 2D materials in bulk form  start extracting information
Database of agreed 2D materials in single layer form  start extracting information
Construction of 2D heterostructure database:
Database experimental information (need input)
Identify monolayer space-group
Implementing criterion for generating heterostructures
Calculation of electronic properties under strain

26. Thank You

27. Previous work on 2D materials

28. Designing new materials

29. Designing new materials