Critical change in the Fermi surface of iron arsenic superconductors at the onset of superconductivity

Details Critical change in the Fermi surface of iron arsenic superconductors at the onset of superconductivity Critical change in the Fermi surface of iron arsenic superconductors at the onset of superconductivity

2009-10-09

arxiv.org/abs/0910.1799v2

Nature Physics 6, 419 (2010)

Physics

Condensed Matter

Superconductivity

Updated version accepted in Nature Physics

Scientific paper

10.1038/NPHYS1656

The phase diagram of a correlated material is the result of a complex interplay between several degrees of freedom, providing a map of the material's behavior. One can understand (and ultimately control) the material's ground state by associating features and regions of the phase diagram, with specific physical events or underlying quantum mechanical properties. The phase diagram of the newly discovered iron arsenic high temperature superconductors is particularly rich and interesting. In the AE(Fe1-xTx)2As2 class (AE being Ca, Sr, Ba, T being transition metals), the simultaneous structural/magnetic phase transition that occurs at elevated temperature in the undoped material, splits and is suppressed by carrier doping, the suppression being complete around optimal doping. A dome of superconductivity exists with apparent equal ease in the orthorhombic / antiferromagnetic (AFM) state as well as in the tetragonal state with no long range magnetic order. The question then is what determines the critical doping at which superconductivity emerges, if the AFM order is fully suppressed only at higher doping values. Here we report evidence from angle resolved photoemission spectroscopy (ARPES) that critical changes in the Fermi surface (FS) occur at the doping level that marks the onset of superconductivity. The presence of the AFM order leads to a reconstruction of the electronic structure, most significantly the appearance of the small hole pockets at the Fermi level. These hole pockets vanish, i. e. undergo a Lifshitz transition, at the onset of superconductivity. Superconductivity and magnetism are competing states in the iron arsenic superconductors. In the presence of the hole pockets superconductivity is fully suppressed, while in their absence the two states can coexist.

Affiliated with

Also associated with

No associations

Rating

Critical change in the Fermi surface of iron arsenic superconductors at the onset of superconductivity does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Critical change in the Fermi surface of iron arsenic superconductors at the onset of superconductivity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Critical change in the Fermi surface of iron arsenic superconductors at the onset of superconductivity will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-51902