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Effect of pressure on the competing phases in FeSe and BaFe<sub>2</sub>As<sub>2</sub>: Insights from specific heat measurements and beyond

Invited

Abstract

Understanding the phase interplay in iron-based superconductors is considered to be crucial for unravelling the mechanism behind their superconductivity. In this talk, we focus on new insights into the phase interplay under pressure of two members, FeSe and BaFe2As2, from specific heat under pressures [1] up to ~ 2.5 GPa.
For FeSe [2], we show that superconductivity is bulk and competes with magnetism, whenever present. In addition, we conclude that, whenever magnetism is present, magnetic and superconducting fluctuations exist across wide ranges of pressure above their respective, bulk transition temperatures.
For Ba(Fe1-xCox)2As2 [3], we argue that the behavior of the nematic transition under pressure is intimately linked to changes of the Fermi surface topology. We complement these data by presenting the first study of elastoresistance under pressure [4] on BaFe2As2, which might allow to study the interplay of nematicity and superconductivity under pressure.
[1] Gati et al., Rev. Sci. Instrum. 90, 023911 (2019); [2] Gati et al., PRL 123, 167002 (2019); [3] Gati et al., PRB 100, 064512 (2019); [4] Gati et al., in preparation.

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Presenters

  • Elena Gati

    Iowa State University, Ames Laboratory, Ames Lab

Authors

  • Elena Gati

    Iowa State University, Ames Laboratory, Ames Lab

  • Li Xiang

    Ames Laboratory and Iowa State University, Iowa State University, Ames Laboratory, Iowa State University

  • Sergey L. Bud'ko

    Iowa State University, Ames Laboratory and Iowa State University, Ames Lab, Ames laboratory, Ames, IA, Department of Physics & Astronomy, Iowa State University/Ames Laboratory, Ames Laboratory, Department of Physics and Astronomy, Iowa State University/Ames Laboratory, Iowa State University and Ames Laboratory, Iowa State University, Ames Laboratory, Division of Materials Sciences & Engineering, Ames Lab and Iowa State University, Iowa State University/Ames Laboratory

  • Paul C Canfield

    Iowa State University, Ames Laboratory and Iowa State University, Ames Lab, Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA, Ames laboratory, Ames, IA, Ames Laboratory, Iowa State University, Department of Physics & Astronomy, Iowa State University/Ames Laboratory, Department of Physics and Astronomy, Iowa State University/Ames Laboratory, Iowa State University and Ames Laboratory, Iowa State University, Ames Laboratory, Department of Physics and Astronomy, Iowa State University, Division of Materials Sciences & Engineering, Ames Lab and Iowa State University, Department of Physics and Astronomy, Ames Laboratory/Iowa State Univeristy, Iowa State University/Ames Laboratory