Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 52: Superconductivity: Fe-based Superconductors - FeSe and LiFeAs
TT 52.5: Vortrag
Mittwoch, 14. März 2018, 10:30–10:45, HFT-FT 101
Evolution of the Fermi surface across a clean nematic quantum phase transition in FeSe1−xSx — •Pascal Reiss1, David Graf2, Amir A. Haghighirad3, and Amalia I. Coldea1 — 1Clarendon Laboratory, Oxford University, UK — 2NHMFL, Tallahassee, USA — 3IFP, Karlsruhe Institute of Technology, GER
The interplay between superconductivity and long-range electronic orders is an intensely studied subject. Iron-based superconductors offer a fruitful field to investigate the role of magnetic order, however the concomitant instability towards nematic (orbital) order requires to be disentangled. For this purpose, the isoelectronic doping series FeSe1−xSx is ideally suited. Undoped FeSe displays nematic but no long-range magnetic order, and becomes superconducting below 9 K. Applied pressure suppresses the nematic transition towards 0 K, but the nematic quantum phase transition is masked by an emerging magnetic phase stabilising superconductivity up to 37 K [1].
With sulphur doping, magnetic order is quickly suppressed, and the nematic quantum phase transition is unmasked [2,3]. We will present transport and TDO measurements as a function of pressure and fields up to 45 T, and – for the first time – we will follow the evolution of the Fermi surface and the strength of electronic correlations across a nematic quantum phase transition.
We acknowledge funding from the EPSRC UK (EP/I004475/1), the NSF and the State of Florida.
S. Medvedev et al., Nat. Mater. (2009)
K. Matsuura et al., Nat. Commun. (2017)
L. Xiang et al., PRB (2017)