Unconventional Charge Density Wave Order in the Pnictide Superconductor Ba(Ni1-xCox)2As2
Unconventional Charge Density Wave Order in the Pnictide Superconductor Ba(Ni1-xCox)2As2
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DOI：
10.1103/physrevlett.122.147601
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发表时间：
2019-04-12
影响因子：
8.6
通讯作者：
Abbamonte, Peter
中科院分区：
文献类型：
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作者：
Lee, Sangjun;de la Pena, Gilberto;Abbamonte, Peter
BA（Ni1-XCOX）（2）AS-2是Pnictide高温超导体BA（Fe1-XCOX）（2）AS-2的结构同源物，其中Fe原子被Ni替换。超导性在该系统中受到高度抑制，达到最大T-C = 2.3 K，而其基于铁的表亲中的24 K则尚不清楚该T-C抑制的起源。使用X射线散射，我们表明BA（Ni1-XCOX）（2）AS-2在其三斜相变时表现出单向电荷密度波（CDW）。 CDW不一致，表现出相当大的晶格失真，并伴随着光发射中的alpha fermi表面口袋的出现[B. Zhou等人，物理。 Rev. B 83，035110（2011）]，表明它是通过非常规机制形成的。 CO掺杂抑制了CDW，与基于铁的超导体中的抗铁磁性行为平行。我们的研究表明，Pnictide超导体可以表现出竞争性的CDW顺序，这可能是该系统中T-C抑制的起源。
Ba(Ni1-xCox)(2)As-2 is a structural homologue of the pnictide high temperature superconductor, Ba(Fe1-xCox)(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(Ni1-xCox)(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 alpha Fermi surface pockets in photoemission [B. Zhou et al., Phys. Rev. B 83, 035110 (2011)], 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.