New evidence for orbital modification of iron-based superconductors above the structural transition temperature (from Dr. Maw-Kuen Wu group)
Scientists from Institute of Physics, Academia Sinica, examine the responses of nonthermal quasiparticles with respect to orbital modifications in the temperature range across the structural phase transition in iron-chalcogenide superconductors. The carrier dynamics shows the emergence of gap-like quasiparticles (associated to a ~36 meV energy gap) with a coincident transfer of the optical spectral weight in the visible range, at temperatures above the structural distortion. Together with a distinct alteration in the transport property, the observations reflect the nature of the short-range charge and/or orbital orders that cause Fermi surface reconstruction and the gap opening. This study not only provides the first evidence for the short-range orders above the structural phase transition, but also supports the picture that the nematicity plays an important role in the precursor state of high- Tc superconductors. The findings are published in Physical Review Letters 108, 267002 on June 26, 2012.
This study was led by Dr. Maw-Kuen Wu in Academia Sinica and collaborated with National Taiwan University and National Taiwan Normal University. This work was jointly sponsored the Academia Sinica Thematic project and the National Science Council grant.
