Interplay of stripe and double-Q magnetism with superconductivity in Ba1 -xKxFe2As2 under the influence of magnetic fields
Abstract
At x ≈0.25 Ba1 -xKxFe2As2 undergoes a novel first-order transition from a fourfold symmetric double-Q magnetic phase to a twofold symmetric single-Q phase, which was argued to occur simultaneously with the onset of superconductivity [Böhmer et al., Nat. Commun. 6, 7911 (2015), 10.1038/ncomms8911]. Here, by applying magnetic fields up to 10 T, we investigate in more detail the interplay of superconductivity with this magnetostructural transition using a combination of high-resolution thermal-expansion and heat-capacity measurements. We find that a magnetic field suppresses the reentrance of the single-Q orthorhombic phase more strongly than the superconducting transition, resulting in a splitting of the zero-field first-order transition. The suppression rate of the orthorhombic reentrance transition is stronger for out-of-plane than for in-plane fields and scales with the anisotropy of the superconducting state. These effects are captured within a phenomenological Ginzburg-Landau model, strongly suggesting that the suppression of the reentrant orthorhombic single-Q phase is primarily linked to the field-induced weakening of the superconducting order. Not captured by this model is, however, a strong reduction in the orthorhombic distortion for out-of-plane fields, which deserves further theoretical attention.
- Publication:
-
Physical Review B
- Pub Date:
- August 2023
- DOI:
- 10.1103/PhysRevB.108.054504
- arXiv:
- arXiv:2212.01183
- Bibcode:
- 2023PhRvB.108e4504W
- Keywords:
-
- Condensed Matter - Superconductivity;
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- doi:10.1103/PhysRevB.108.054504