Unconventional charge density wave order in the pnictide superconductor Ba(Ni1-xCox)2As2

Sangjun Lee, Gilberto De La Penã, Stella X.L. Sun, Matteo Mitrano, Yizhi Fang, Hoyoung Jang, Jun Sik Lee, Chris Eckberg, Daniel Campbell, John Collini, Johnpierre Paglione, F. M.F. De Groot, Peter Abbamonte

Research output: Contribution to journalArticlepeer-review

Abstract

Ba(Ni1-xCox)2As2 is a structural homologue of the pnictide high temperature superconductor, Ba(Fe1-xCox)2As2, in which the Fe atoms are replaced by Ni. Superconductivity is highly suppressed in this system, reaching a maximum Tc=2.3 K, compared to 24 K in its iron-based cousin, and the origin of this Tc suppression is not known. Using X-ray scattering, we show that Ba(Ni1-xCox)2As2 exhibits a unidirectional charge density wave (CDW) at its triclinic phase transition. The CDW is incommensurate, exhibits a sizable lattice distortion, and is accompanied by the appearance of α Fermi surface pockets in photoemission [B. Zhou et al., Phys. Rev. B 83, 035110 (2011)PRBMDO1098-012110.1103/PhysRevB.83.035110], suggesting it forms by an unconventional mechanism. Co doping suppresses the CDW, paralleling the behavior of antiferromagnetism in iron-based superconductors. Our study demonstrates that pnictide superconductors can exhibit competing CDW order, which may be the origin of Tc suppression in this system.

Original languageEnglish (US)
Article number147601
JournalPhysical review letters
Volume122
Issue number14
DOIs
StatePublished - Apr 12 2019

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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