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

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

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

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

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

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

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

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

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.

Database setup (again just for reference) 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Thank You

Previous work on 2D materials

Designing new materials

Designing new materials