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. BaNi2As2, like its well-known iron-based analog BaFe2As2, 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 B1g 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 BaFe2As2, the structural and CDW order parameters in BaNi2As2 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 BaNi2As2.
@article{arxiv.2205.14339,
title = {Spectral Evidence for Unidirectional Charge Density Wave in Detwinned BaNi$_2$As$_2$},
author = {Yucheng Guo and Mason Klemm and Ji Seop Oh and Yaofeng Xie and Bing-Hua Lei and Sergey Gorovikov and Tor Pedersen and Matteo Michiardi and Sergey Zhdanovich and Andrea Damascelli and Jonathan Denlinger and Makoto Hashimoto and Donghui Lu and Sung-Kwan Mo and Rob G. Moore and Robert J. Birgeneau and David J. Singh and Pengcheng Dai and Ming Yi},
journal= {arXiv preprint arXiv:2205.14339},
year = {2025}
}