Modelling of Materials and Nanotechnologies: From Ab Initio to Macro-Simulations

1. Modelling of Materials and Nanotechnologies: From Ab Initio to Macro-Simulations • Dr. Jérôme Cornil • Jerome.Cornil@umons.ac.be Laboratory for Chemistry of Novel Materials University of Mons, Belgium Industrial Technologies, June 2012, Aarhus

2. Multiscale Modelling ms to ks 104-106 100-104 / fs to ns 10-100 http://www.cse.sc.edu/~heyden/Multi-ScaleModelling.html

3. Quantum-Chemistry Key quantity : Wavefunction Time-independent Schrödinger equation H  = E  Approximations F i (r) = i i (r) Hartree-Fock equation Averaged electronic interactions  Correlation error : E0 – EHF

4. Quantum-Chemistry Post-Hartree Fock methods Perturbative Variational Configuration Interaction (CI) Möller Plesset (MP2, MP3,..) Very time consuming  CI = C0 SCF +  CJ Jab +  CKKab + ... cd J K Truncations needed  Access to excited states  Coupled Cluster (CC) CASSCF

5. Density Functional Theory (DFT) Key quantity : Electronic density Hohenberg-Kohn functional E0 [0] = FHK [0] +  0(r ) Vext dr F [] = TS[] + J [] + EXC[] Exchange-correlation energy fKS i = i i Kohn-Sham equation Need to find expressions for EXC Self-interaction error  Access to excited states (TD-DFT) 

6. DFT and HF - Explicit account of electrons  - Limitation in the size of the system (a few hundred atoms)  Semi-empirical Hartree-Fock techniques - Poor description of van der Waals interactions  - Use of Periodic Boundary Conditions (PBC)  Slab approach CH3S on gold Gaussian, Turbomole, VASP, SIESTA, DMOL, CRYSTAL, MOPAC, ABINIT…

7. Phenomenological Models Vibrations Coupling Sites - Charge transport Tight-binding models (Tight-binding DFT)

8. Force Field Calculations E = Bending Stretching Out-of-plane Torsions H-bonds Non bonded interactions (van der Waals, Coulombic)

9. Force Fields Parameterized from quantum-chemical calculations and/or experimental data Stretching Bending Vb= kb ( – 0)2 Vs= ks (r – r0)2 Harmonic approximation van der Waals Coulomb qi qj Vc=  Vw= (Aij / r12 – Bij / r6) 4  0r r Lennard-Jones potential

10. Force Fields - No explicit account of electrons  - Parameterization from QC calculations or experimental data  - Large size of the systems (many thousands)  - Explicit term for vdW interactions  Organic Specific force fields  MM2, MM3 UFF (Universal Force Field) COMPASS (Condensed-phase Optimized Molecular Potentials for Atomistic Simulation Studies) Biologic (proteins, nucleic acids) AMBER (Assisted Model Building with Energy Refinement) CHARMM (Chemistry at HARvard using Molecular Mechanics) Reliable description of H-bonds Materials Studio, GROMACS, NAMD, TINKER, LAMMPS

11. Molecular Simulations Molecular Mechanics Molecular Dynamics E(x) E(x) x x Search for equilibrium structures Exploration of the conformational space + Simulated Annealing + Monte Carlo PBC : Available Quantum dynamics : Car Parrinello (CPMD)

12. QM/MM - Embedding of a quantum part in a classical medium - Interest in using polarizable force field T. Van Voorhis and co, Acc. Chem. Res. 7, 43, 995

13. Coarse-Graining Atomistic description  Effective interaction potentials Key role of the parameterization  Claudio Zannoni, University of Bologna

14. Coarse-Graining C. Zannoni, J. Mater. Chem., 11, 2637, 2001

15. Kinetic Monte Carlo (KMC) ij - Random choice of the destination : i j - Probability of transfer - Random number between 0 and 1 :  If   Pij, the transfer is accepted with a time ij-1 If   Pij, the transfer is not accepted

16. Continuum Models – Device Modelling • Tools to solveclassicaldifferentialequationsfedwith input parameterscoming • fromexperiment or molecular simulations (FiniteElementMethods – FEM) Comsol, Abaqus - Specific to the applications (fluid, charges…) - Charges  Drift-diffusion model Charge density profile !! - Fluid  Navier-Stokes equation Fluid density profile !! - Structural mechanics - Implicit account of chemistry concepts

17. AMCOS 233502 – Materials as CO2 removers Zeolite framework for selective sorption of CO2 Force Field (Dreiding) Molecular Dynamics, Monte Carlo DFT (partial charges) Amount of gas sorbed (isotherms) CO2 diffusion J. Mater. Chem., 2010, 20, 7676-7681

18. S D G HYMEC 263073 Non volatile hybrid memories - Gold nanoparticles in organic semiconductors - Switch via charging of the nanoparticles Quantum-chemistry (Electronic structure of the NPs and molecules) Kinetic Monte Carlo or Master Equation (mobility) Drift – Diffusion Model (I/V characteristics)

19. MAHEATT 227541 Search for new cathode materials in Li-ion batteries for increased storage DFT – Structure and stability of the materials Intercalation and deintercalation of Li DFT - MD Li-ion mobility

20. MODIFY 228320 Stress induced mechanical properties of soft-based adhesives (acrylic polymers) Force field (interaction polymer/substrate – formation of H bonds) Coarse graining (interaction between particles) Finite element (bulk rheological properties – debonding mechanisms)

21. MORDRED 261868 Nanoelectronics Random defects + trapped charges DFT

22. MULTIHY 263335 DFT (energy barriers / binding energies) Tight binding  Grain boundaries Kinetic Monte Carlo (hydrogen diffusion as a function of defect, T, stress) Finite Element Method (macroscopic model for hydrogen diffusion)

23. HYPOMAP 233482 New materials for hydrogen storage / proton exchange membranes DFT Chemisorption / physisorption of H2 in metal hydrides and MOFs Proton diffusion rates DFTB up to 1000 – 10000 atoms

24. POCO 213939 Interactions of functionalized carbon nanotubes with polymer matrices Force field calculations Interaction energies Pull-out energy FEM Mechanical properties

25. ADGLASS 229205 Adhesion and cohesion at interfaces in high performance glassy systems Anti-adherent properties for proteins Adhesion between glassy SiO2 and crystalline TiO2 for solar collectors Hybrid quantum-mechanical atomistic modelling Quantum chemistry involved for the formation of chemical bonds, proton transfer Model development !

26. Dynamag 233552 and Magnonics 228673 Spin wave spectra and dispersion DFT (Exchange energy) Magnonic devices Finite Element Micromagnetic package New models for new physics !!

27. MINOTOR 228424 Self-Assembled Monolayers HS-C16H33 20 nm metal 20 nm metal + HS-C16H33 20 nm metal + HS-C2H4C8F17 HS-C2H4C8F17 Work function [eV] Au Ag metal (+SAM) Tuning of injection barriers Bert de Boer et al., Adv. Mater., 2005, 17, 621

28. Theoretical Methodology CH3S  (bridge) = -1.19 eV  (fcc) = -1.52 eV SIESTA – DFT – GGA (PBE)

29. Perspectives - Linear scaling - Dispersion forces at the quantum level - Hybrid approaches QM/MM - Polarizable force fields, reactive force fields - More links between the atomistic and macroscopic world - Automatized procedure for multiscale modelling

30. MMM@HPC: e-infrastructure Proposal , pp. 5−8

31. Partners Nokia CSC STFC KIT UMons Sony CEA CIN UPA www.multiscale-modelling.eu

32. Application Example Workflow • Film deposition (or MD) • Generate disordered film morphologies • QM calculations of hopping sites • Calculate HOMO, LUMO, LUMO+1 etc energies. • Electronic couplings reorganization energies • Calculate charge hopping rates • Kinetic Monte Carlo (KMC) • Calculate charge (electron-hole) mobility • Calculate current density J. J. Kwiatkowski, J. Nelson, H. Li, J. L. Bredas, W. Wenzel, and C. Lennartz, Phys. Chem. Chem. Phys., 2008, 10, 1852–1858. For the science: see talk by J. Cornil

33. Graphical User Interface for individual codes and entire workflows Gridbeans Parameters can be adjusted UNICORE Rich Client Workflow Embedded visualisation with Jmol

34. Control flow: Example Stefan Bozic – ISGC, Academia Sinica Taipei, February 29, 2012

35. Coverage of different scales macroscopic scale molecular scale electronic scale ~ 10-6 m ~ 10-8 m ~ 10-10 m Many gridbeans for high performance codes already exits