Magnetoelectric materials are insulators whose magnetic properties can be controlled by application of external electric fields. This possibility opens the door to many interesting applications, such as the development of magnetic memories that would be writeable by means of electric fields, thus solving Joule-heating problems that currently complicate the miniaturization of MRAMs. We have recently introduced a method for first-principles calculations of magnetoelectric effects. Thanks to this technique, we are now in a position to make a significant contribution to the experimental search for new materials that display robust magnetoelectric properties at room temperature.

Jacek C. Wojdeł and Jorge Íñiguez, Physical Review Letters 103, 267205 (2009)
Jorge Íñiguez, Physical Review Letters 101, 117201 (2008)

January 2010

Ferroelectric and piezoelectric oxides constitute a very active research area within our group. Our work is very wide in scope, ranging from the calculation of electronic transport through ultra-thin ferroelectric tunnel junctions using non-equilibrium Green’s functions methods, to the computation of the thermodynamic properties of ferroelectrics using Monte Carlo and Molecular Dynamics techniques. The two (somehow old) highlighted examples illustrate our ability to compute phase diagrams and relate our first-principles results to traditional phenomenological theories.

Jorge Íñiguez and David Vanderbilt, Physical Review Letters 89, 115503 (2002)
Jorge Íñiguez, S. Ivantchev, J.M. Perez-Mato and Alberto Garcia, Physical Review B 63, 144103 (2001)

April 2009

Our quantum mechanical simulation methods are ideally suited to investigate physical phenomena that cannot be understood within the usual wisdom of the field. We often collaborate with experimental colleagues to provide such a physical understanding of novel materials and effects. A recent example is the study of initinite layer SrFeO₂, a compound in which Fe²⁺ cations remain in a perfectly square planar coordination down to very low temperatures, thus defying what would be predicted from crystal field theory. Our calculations revealed the physical mechanisms responsible for this effect, and predicted deviations from this behavior depending on composition (e.g., in CaFeO₂).

C. Tassel, J.M. Pruneda, H. Kageyama, J. Íñiguez, E. Canadell et al., J. Am. Chem. Soc. 131, 221 (2009)
J.M. Pruneda, J. Íñiguez, E. Canadell, H. Kageyama and M. Takano, Physical Review B 78, 115101 (2008)

April 2009

Developing safe and efficient methods for storing hydrogen at ambient conditions is critical for the progress of fuel-cell technologies. Current efforts focus on obtaining hydrogen-binding interactions in the range that is appropriate for applications, namely, about 0.5 eV. First-principles methods enable a detailed analysis of the H₂ binding interactions, and are thus ideally suited for the search of novel solid state systems for hydrogen storage. Our latest work has focused on graphites intercalated with light metal atoms, and suggest that alkaline-earths, like Be or Mg, could lead to useful storage properties.

Works on metal assisted carbons for hydrogen storage:
Manuel Cobian and Jorge Íñiguez, Journal of Physics: Condensed Matter 20, 285212 (2008)
Jorge Íñiguez, Wei Zhou and Taner Yildirim, Chemical Physics Letters 444, 140 (2007)
Taner Yildirim, Jorge Íñiguez and S. Ciraci, Physical Review B 72, 153403 (2005)

Works on solid state hydrogen storage:
Jorge Íñiguez and Taner Yildirim, Journal of Physics: Condensed Matter 19, 176007 (2007)
Jorge Íñiguez and Taner Yildirim, Applied Physics Letters 86, 103109 (2005)
Jorge Íñiguez, Taner Yildirim, T.J. Udovic, M. Sulic and C.M. Jensen, Physical Review B 70, 060101 (2004)