Proximity of iron pnictide superconductors to a quantum tricritical point
- Author(s)
- Gianluca Giovannetti, Carmine Ortix, Martijn Marsman, Massimo Capone, Jeroen Van den Brink, Jose Lorenzana
- Abstract
In several materials, unconventional superconductivity appears nearby a quantum phase transition where long-range magnetic order vanishes as a function of a control parameter like charge doping, pressure or magnetic field. The nature of the quantum phase transition is of key relevance, because continuous transitions are expected to favour superconductivity, due to strong fluctuations. Discontinuous transitions, on the other hand, are not expected to have a similar role. Here we determine the nature of the magnetic quantum phase transition, which occurs as a function of doping, in the iron-based superconductor LaFeAsO(1-x)F(x). We use constrained density functional calculations that provide ab initio coefficients for a Landau order parameter analysis. The outcome is intriguing, as this material turns out to be remarkably close to a quantum tricritical point, where the transition changes from continuous to discontinuous, and several susceptibilities diverge simultaneously. We discuss the consequences for superconductivity and the phase diagram.
- Organisation(s)
- Computational Materials Physics
- External organisation(s)
- Sapienza University of Rome, Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, Scuola Internazionale Superiore di Studi Avanzati
- Journal
- Nature Communications
- Volume
- 2
- No. of pages
- 6
- DOI
- https://doi.org/10.1038/ncomms1407
- Publication date
- 2011
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103009 Solid state physics, 103015 Condensed matter, 103025 Quantum mechanics, 103036 Theoretical physics
- Portal url
- https://ucris.univie.ac.at/portal/en/publications/proximity-of-iron-pnictide-superconductors-to-a-quantum-tricritical-point(22a0aeee-3043-4711-8a02-bb9c69983549).html