SKM 2021 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 5: Poster Session: Superconductivity
TT 5.9: Poster
Monday, September 27, 2021, 13:30–16:00, P
Unconventional Dynamical Scaling close to a Nematic Quantum Critical Point in FeSe0.89S0.11 — •Pascal Reiss1,2, David Graf3, Amir-Abbas Haghighirad4, Thomas Vojta5, and Amalia Coldea1 — 1Clarendon Laboratory, University of Oxford, UK — 2MPI-FKF, Stuttgart, Germany — 3NHMFL, Tallahassee, USA — 4IQMT, Karlsruhe Institute of Technology, Germany — 5Department of Physics, Missouri University of Science and Technology, USA
In the vicinity of quantum critical points, the interplay between electronic and structural order can lead to new and unconventional phases. Of particular interest is the electronic nematic order, with its predicted long-range interactions mediated through the lattices shear modes. Here, we first review the nature of the nematic QCP in FeSe0.89S0.11 under hydrostatic pressure. Then, we will demonstrate that the magnetoresistivity close to the QCP obeys a scaling relation over two decades in temperature with diverging critical exponents at low temperatures, in stark contrast to the usual ansatz using fixed exponents. We discuss our findings in the context of disconnected static and dynamic quantum fluctuations, a coupling between electronic and phononic modes, and topological changes of the Fermi surface. These lead to the emergence of an atypical non-zero energy scale at the QCP which strongly affects superconductivity. arXiv:2103.07991
We acknowledge funding from the EPSRC (EP/I004475/1, EP/I017836/1, EP/M020517/1, EP/N01085X/1), the NSF (DMR-1157490, DMR-1828489), the State of Florida, and the John Fell Fund.