First Principles Simulations and Modeling

First Principles Simulations and ModelingComputer modeling has grown over the years into a scientific discipline on its own. Models are utilized to assess real-world phenomena maybe too complex to be analyzed in the laboratory or under hypotheses at a fraction of the cost of undertaking the actual activities. Models in industry, government, and educational institutions shorten design cycles, reduce costs, and enhance knowledge.

In Physics, the modeling of materials through what is known as “first-principles” has become a major research field. By “first-principles” one understands the use of the fundamental quantum mechanical laws of nature and nothing else. The properties of the materials should emerge from the numerical solution of these laws. The models here are actually a faithful representation of reality, but in a controlled environment.

Researchers at IFIMAC have a long-standing and well-deserved international reputation on theoretical modeling and, in particular, on the development of efficient first-principles techniques for the simulation of the electronic and structural properties of complex materials. All the other research lines at IFIMAC benefit one way or another from this expertise. This knowledge not only benefits fundamental research, but can also be transferred directly into the society through spin-offs.

This is a list of codes and computational techniques being developed and implemented:

  • SIESTA code for large-scale DFT simulations.First Principles Simulations and Modeling
  • ANT code for DFT-based electronic quantum transport calculations.
  • FIREBALL code for DFT local-orbital molecular-dynamics.
  • Hybrid Quantum Mechanics/Molecular Mechanics (QM/MM) method for the simulation of biomolecules.
  • Non-adiabatic molecular dynamics.
  • MOLCAS code for wave function theory electronic structure calculations.

Research topics:

  • Molecular electronics.
  • Bi-dimensional crystals.
  • Interfaces of organic semiconductors
  • Chemical reactions in biomolecules.
  • Atomic, electronic, and dynamical properties of semiconductor surfaces.
  • Nanowires and nanocontacts.
  • Excited states off-element ions in solids.

Key References

  1. Emergent Heavy Fermion Behavior at the Wigner-Mott Transition
    Jaime Merino, Arnaud Ralko and Simone Fratini
    Physical Review Letters 111, 126403 (2013). [URL]
  2. Topologically Protected Quantum Transport in Locally Exfoliated Bismuth at Room Temperature
    C. Sabater, D. Gosálvez-Martínez, J. Fernández-Rossier, J.G. Rodrigo, C. Untiedt and J.J. Palacios
    Physical Review Letters 110, 176802 (2013). [URL]
  3. Energy Level Alignment in Organic-Organic Heterojunctions: The TTF/TCNQ Interface
    Juan I. Beltran, Fernando Flores, Jose I. Martinez, et al.
    Journal of Physical Chemistry C, 117, 3888, (2013). [URL]
  4. Competing charge ordering and Mott phases in a correlated Sn/Ge(111) two-dimensional triangular lattice
    R. Cortes, A. Tejeda, J. Lobo-Checa, et al.
    Physical Review B 88 125113 (2013). [URL]
  5. Density, structure, and dynamics of water: The effect of van der Waals interactions
    J. Wang et al.
    J. Chem. Phys. 134 024516 (2011). [URL]
  6. C6H6/Au(111): Interface dipoles, band alignment, charging energy, and van der Waals interaction
    E. Abad, Y.J. Dappe, J.I. Martinez, et al.
    Journal of Chemical Physics 134, 044701, (2011). [URL]
  7. Efficient Implementation of a van der Waals Density Functional: Application to Double-Wall Carbon Nanotubes
    G. Roman-Perez and J. M. Soler
    Phys. Rev. Lett. 103 096102 (2009). [URL]
  8. Modelling energy level alignment at organic interfaces and density functional theory
    F. Flores, J. Ortega and H. Vazquez
    Physical Chemistry Chemical Physics 11 8658, (2009). [URL]
  9. Vacancy-induced magnetism in graphene and graphene ribbons
    J.J. Palacios, J. Fernández-Rossier and L. Brey
    Physical Review B 77 (19), 195428 (2008) . [URL]
  10. Giant magnetoresistance in ultrasmall graphene based devices
    F. Muñoz-Rojas, J. Fernández-Rossier, J.J. Palacios
    Physical review letters 102 (13), 136810 (2008). [URL]
  11. Magnetism in graphene nanoislands
    J. Fernandez-Rossier and J.J. Palacios
    Physical Review Letters 99 (17), 177204 (2007). [URL]
  12. Soft phonon, dynamical fluctuations, and a reversible phase transition: Indium chains on silicon
    C. Gonzalez, F. Flores and J. Ortega
    Physical Review Letters 96 136101 (2006). [URL]
  13. Energy level alignment at organic heterojunctions: Role of the charge neutrality level
    H. Vazquez, W. Gao, F. Flores, et al.
    Physical Review B 71 041306, (2005). [URL]
  14. Dipole formation at metal/PTCDA interfaces: role of the charge neutrality level
    H. Vazquez, R. Oszwaldowski, P. Pou, et al.
    EUROPHYSICS LETTERS 65 802, (2004). [URL]
  15. Phonon softening, chaotic motion, and order-disorder transition in Sn/Ge(111)
    D. Farias, W. Kaminski, J. Lobo, et al.
    Physical Review Letters 91 016103, (2003). [URL]
  16. First-principles approach to electrical transport in atomic-scale nanostructures
    J.J. Palacios, A.J. Pérez-Jiménez, E. Louis, E. SanFabián and J.A. Vergés
    Physical Review B 66 (3), 035322 (2002). [URL]
  17. The SIESTA method for ab initio order-N materials simulation
    J. M. Soler et al.
    J. Phys: Condens. Matter, 14 2745-2779 (2002). [URL]
  18. Surface soft phonon and the root 3 x root 3 <-> 3 x 3 phase transition in Sn/Ge(111) and Sn/Si(111)
    R. Perez, J. Ortega and F. Flores
    Physical Review Letters 86, 4891 (2001). [URL]
  19. Fullerene-based molecular nanobridges: A first-principles study
    J.J. Palacios, A.J. Pérez-Jiménez, E. Louis and J.A. Vergés
    Physical Review B 64 (11), 115411 (2001). [URL]
  20. Ab initio structural, elastic, and vibrational properties of carbon nanotubes
    D. Sanchez-Portal et al.
    Phys. Rev. B 59 12678-12688 (1999). [URL]
  21. Dynamical fluctuations as the origin of a surface phase transition in Sn/Ge(111)
    J. Avila, A. Mascaraque, E.G. Michel, et al
    Physical Review Letters 82, 442 (1999). [URL]
  22. Self-consistent order-N density-functional calculations for very large systems
    P. Ordejon, E. Artacho, and J. M. Soler
    Phys. Rev. B, 53 10441-10444 (1996). [URL]
  23. Capacitance spectroscopy in quantum dots: Addition spectra and decrease of tunneling rates
    J.J. Palacios, L. Martin-Moreno, G. Chiappe, E. Louis and C. Tejedor
    Physical Review B 50 (8), 5760 (1994). [URL]