Decoupling of lattice and orbital degrees of freedom in an iron-pnictide superconductor

oleh: C. E. Matt, O. Ivashko, M. Horio, J. Choi, Q. Wang, D. Sutter, N. Dennler, M. H. Fischer, S. Katrych, L. Forro, J. Ma, B. Fu, B. Q. Lv, M. v. Zimmermann, T. K. Kim, N. C. Plumb, N. Xu, M. Shi, J. Chang

Format: Article
Diterbitkan: American Physical Society 2021-06-01

Deskripsi

The 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 electron-doped iron-pnictide superconductor Pr_{4}Fe_{2}As_{2}Te_{0.88}O_{4} (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}∼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.