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arXiv · 2205.14339

Spectral Evidence for Unidirectional Charge Density Wave in Detwinned BaNi$_2$As$_2$

Yucheng Guo·Mason Klemm·Ji Seop Oh·Yaofeng Xie·Bing-Hua Lei·Sergey Gorovikov·Tor Pedersen·Matteo Michiardi·Sergey Zhdanovich·Andrea Damascelli·Jonathan Denlinger·Makoto Hashimoto·Donghui Lu·Sung-Kwan Mo·Rob G. Moore·Robert J. Birgeneau·David J. Singh·Pengcheng Dai·Ming Yi
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Abstract

The emergence of unconventional superconductivity in proximity to intertwined electronic orders is especially relevant in the case of iron-based superconductors. Such order consists of an electronic nematic order and a spin density wave in these systems. BaNi$_2$As$_2$, like its well-known iron-based analog BaFe$_2$As$_2$, also hosts a symmetry-breaking structural transition that is coupled to a unidirectional charge density wave (CDW), providing a novel platform to study intertwined orders. Here, through a systematic angle-resolved photoemission spectroscopy study combined with a detwinning $B_1g$ uniaxial strain, we identify distinct spectral evidence of band evolution due to the structural transition as well as CDW-induced band folding. In contrast to the nematicity and spin density wave in BaFe$_2$As$_2$, the structural and CDW order parameters in BaNi$_2$As$_2$ are observed to be strongly coupled and do not separate in the presence of uniaxial strain. Our measurements point to a likely lattice origin of the CDW in BaNi$_2$As$_2$.

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Yucheng Guo, Mason Klemm, Ji Seop Oh, Yaofeng Xie, Bing-Hua Lei, Sergey Gorovikov, Tor Pedersen, Matteo Michiardi, Sergey Zhdanovich, Andrea Damascelli, Jonathan Denlinger, Makoto Hashimoto, Donghui Lu, Sung-Kwan Mo, Rob G. Moore, Robert J. Birgeneau, David J. Singh, Pengcheng Dai, Ming Yi. 2022-05-28. Spectral Evidence for Unidirectional Charge Density Wave in Detwinned BaNi$_2$As$_2$. https://doi.org/10.1103/physrevb.108.l081104

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