Matt, C. E.Ivashko, O.Horio, M.Choi, J.Wang, Q.Sutter, D.Dennler, N.Fischer, M. H.Katrych, S.Forro, L.Ma, J.Fu, B.Lv, B. Q.Zimmermann, M., VKim, T. K.Plumb, N. C.Xu, N.Shi, M.Chang, J.2021-07-172021-07-172021-07-172021-06-2110.1103/PhysRevResearch.3.023220https://infoscience.epfl.ch/handle/20.500.14299/180102WOS:000664651400005The interplay between structural and electronic phases in iron-based superconductors is a central theme in the search for the superconducting pairing mechanism. While electronic nematicity is competing with superconductivity, the effect of purely structural orthorhombic order is unexplored. Here, using x-ray diffraction and angle-resolved photoemission spectroscopy, we reveal a structural orthorhombic phase in the electrondoped iron-pnictide superconductor Pr4Fe2As2Te0.88O4 (T-c = 25 K), which is distinct from orthorhombicity in the nematic phase in underdoped pnictides. Despite the high electron doping we find an exceptionally high orthorhombic onset temperature (T-ort similar to 250 K), no signatures of phase competition with superconductivity, and absence of electronic nematic order as the driving mechanism for orthorhombicity. Combined, our results establish a high-temperature phase in the phase diagram of iron-pnictide superconductors and impose strong constraints for the modeling of their superconducting pairing mechanism.Physics, MultidisciplinaryPhysicsanisotropyordertext::journal::journal article::research article