Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 15: Superconductivity: Fe-based Superconductors - Other Materials and Theory
TT 15.14: Talk
Monday, April 1, 2019, 18:45–19:00, H23
Nematic fluctuations close to quantum criticality: a new method for comparing simulations and experiments — •Daniel Jost1,2, Samuel Lederer3, Thomas Böhm1,2, Yoni Schattner4,5, Erez Berg6, Steven Kivelson4, and Rudi Hackl1,2 — 1Walther-Meissner-Institute, 85748 Garching, Germany — 2Physik-Department, TU München, 85748 Garching, Germany — 3Cornell University, 14850 Ithaca, USA — 4Department of Physics, Stanford University, 94305 Stanford, USA — 5Stanford Institute of Material and Energy Science, 94025 Menlo Park, USA — 6Department of Physics, University of Chicago, 60637 Chicago, USA
The comparison of numerical simulations and spectroscopic results is notoriously difficult due to the analytic continuation in the complex energy plane. Additionally, life times and mass enhancement factors must be extracted from the experimental spectra using, e.g., the Kramers-Kronig transformation with the well-known problems resulting from the extrapolations to low and high energies. One way out of this dilemma is a transformation of the experimental results from real to imaginary frequencies which provides us with an imaginary-time-ordered correlation function Λ(τ). From this transformation, one can extract the quantity β Λ(β/2) with β = 1/kBT. In this contribution we derive this quantitiy from the electronic Raman spectra of the iron pnictide Ba(Fe1−xCox)2As2 as a function of doping and temperature. Additionally, we highlight the perspectives of this method with view on quantum criticality and the comparison of experiment and theory.