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Lee S, de la Peña G, Sun SXL, Mitrano M, Fang Y, Jang H, Lee JS, Eckberg C, Campbell D, Collini J, Paglione J, de Groot FMF, Abbamonte P. Unconventional Charge Density Wave Order in the Pnictide Superconductor Ba(Ni_{1-x}Co_{x})_{2}As_{2}. PHYSICAL REVIEW LETTERS 2019; 122:147601. [PMID: 31050473 DOI: 10.1103/physrevlett.122.147601] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 12/14/2018] [Indexed: 06/09/2023]
Abstract
Ba(Ni_{1-x}Co_{x})_{2}As_{2} is a structural homologue of the pnictide high temperature superconductor, Ba(Fe_{1-x}Co_{x})_{2}As_{2}, in which the Fe atoms are replaced by Ni. Superconductivity is highly suppressed in this system, reaching a maximum T_{c}=2.3 K, compared to 24 K in its iron-based cousin, and the origin of this T_{c} suppression is not known. Using x-ray scattering, we show that Ba(Ni_{1-x}Co_{x})_{2}As_{2} 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 T_{c} suppression in this system.
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Affiliation(s)
- Sangjun Lee
- Department of Physics and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
| | - Gilberto de la Peña
- Department of Physics and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
| | - Stella X-L Sun
- Department of Physics and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
| | - Matteo Mitrano
- Department of Physics and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
| | - Yizhi Fang
- Department of Physics and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
| | - Hoyoung Jang
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- PAL-XFEL Beamline Division, Pohang Accelerator Laboratory, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Jun-Sik Lee
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Chris Eckberg
- Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Daniel Campbell
- Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - John Collini
- Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Johnpierre Paglione
- Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - F M F de Groot
- Debye Institute of Nanomaterial Science, Utrecht University, 3584 CA Utrecht, Netherlands
| | - Peter Abbamonte
- Department of Physics and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
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