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.
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.
*The present work was done in collaboration with Anna Böhmer (KIT).
*This work was carried out at Iowa State University and supported by Ames Laboratory, US DOE, under Contract No. DE-AC02- 07CH11358, by the Gordon and Betty Moore Foundation's EPiQS Initiative and the W. M. Keck Foundation.
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Presenters
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Elena Gati
- Iowa State University, Ames Laboratory
- Ames Lab