Andreas Kreyssig

TL;DR: In the case of single crystals, the phase transition from a tetragonal phase to a low-temperature orthorhombic phase near 85 K was detected in this article.

TL;DR: It is proposed that the coupling between orthorhombicity and superconductivity is indirect and arises due to the magnetoelastic coupling, in the form of emergent nematic order, and the strong competition between magnetism andsuperconductivity.

TL;DR: The observation of charge-density-wave correlations in the model cuprate superconductor HgBa2CuO(4+δ) (T(c)=72 K) via bulk Cu L3-edge-resonant X-ray scattering points to a unifying picture in which these two phenomena are preceded at the higher pseudogap temperature by q=0 magnetic order and the build-up of significant dynamic antiferromagnetic correlations.

TL;DR: This work shows that the key structural features in BaFe2As2, namely suppression of the tetragonal-to-orthorhombic phase transition and reduction in the As-Fe-As bond angle and Fe-Fe distance, show the same behaviour under pressure as found in chemically substituted samples, and suggests that modification of the Fermi surface by structural distortions is more important than charge doping for inducing superconductivity in Ba Fe 2As2.

TL;DR: In this paper, the authors synthesize the first-order structural phase transition to a low-temperature orthorhombic phase with a 2-3 K range of hysteresis and coexistence.