Algorithm Development and Techniques in Use

• MECCA: Green's Fct. based KKR-CPA
  • Improved Spherical Approximation for electronic-structure calculations
    e.g., Variational MT zero, and improved representations via saddle points in charge densities.
  • Iterative Block method for complex, non-Hermitian matrices that are O(N) system size.
• Numerical Methods for Electronic Structure Methods
  • Broyden Second Method used in many codes worldwide: (Download broyden.f)
• Cluster Expansions and General Lattice Monte Carlo
• Full-potential Linear Augmented Plane Waves (FLAPW)
• Vienna Atomic Simulation Program (VASP)
• Genetic Algorithms and Programs
• Kinetic Monte Carlo

KKR-CPA electronic-structure methods -- Alloys Energetics and (Dis)Order Effects

MECCA code
• All-electron, scf green's function techniques for O(N^1+e) scaling (N=atoms) and capable of addressing up to 2000 per unit cell on one workstation, and more atoms on scalable-parallel clusters.
• Green's Function can also deal with inhomogeneous (subsitutional) disorder (e.g., concentration profiles around defects) including using the Dynamical Cluster Approximation (DCA) or Non-Local-CPA to handle Atomic Short-Range Order.
• Processing temperatures effect on magnetism and alloy structural defect energies.

First-Principles Multicomponent Phase Diagrams -- Reliable Cluster Expansions

TTK code (Thermodynamic ToolKit)
• DFT-based improved Cluster Expansion for more reliable thermodynamic predictions of alloy thermodynamics.
• Rapid Phase Diagram estimation via the CE and Accurate Mean-Field Theories

Multicomponent Phase Stability -- Concentration Waves

S2 code
• DFT-based (KKR-CPA) linear-response methods for thermodynamic predictions in high-T alloys and comparison to characterization data

Nanoassemblies, Hydrogen Storage and Catalysis

• Accurate prediction of Finite-T Enthalpies of Molecular Solid for Storage Reactions.
• Structural and electronic properties of nanoclusters on supports - prediction of experiment.
• Properties of self-organized polymeric multilayers via analytic model based on non-linear iterative maps.