Dresden 2017 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 70: Superconductivity: Fe-based Superconductors - Theory

TT 70.4: Vortrag

Donnerstag, 23. März 2017, 16:00–16:15, HSZ 103

s+is Superconductivity with incipient bands: doping dependence and STM signatures — •Jakob Böker, Pavel Volkov, and Ilya Eremin — Institut fur Theoretische Physik III, Ruhr-Universität Bochum, D-44801 Bochum, Germany

Motivated by the recent observations of small Fermi energies and comparatively large superconducting gaps, present on bands located below the Fermi energy(incipient bands) in iron-based superconductors, we analyse the doping evolution of superconductivity in a four-band model in the BCS-BEC crossover regime for the iron pnictides. Similar to the BCS case we find that with hole doping the phase difference between superconducting order parameters of the hole bands changes from 0 to π through an intermediate s+is state breaking time-reversal symmetry. However, in the BCS-BEC crossover phase this transition occurs in the region where electron bands are already above the Fermi level and that the chemical potential renormalization leads to significant broadening of the s+is region. This makes the observation of this phase easier in experiment. We further present the qualitative features of the s+is state that can be observed in scanning tunnelling microscopy (STM) experiments.