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arXiv · 2109.10851

First-principles study of the electronic structure of CaKRu$_4$P$_4$

Xinlei Zhao·Fengjie Ma·Zhong-Yi Lu
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Abstract

The recent discovery and studies of 1144-phase compounds, e.g., CaKFe$_4$As$_4$, have attracted significant research interest. In this paper, based on the first-principles density functional calculations, we present a systematic study on the electronic structure of the recently synthetized 1144-type quaternary compound CaKRu$_4$P$_4$. We find that the Ru-based 1144-type compound possesses a different electronic structure from that of iron-based superconductors, even though they share very similar crystallographic structures. In CaKRu$_4$P$_4$, there is no hole-type carrier if spin-orbit interaction is not considered. And a long-range magnetic order is absent in its ground state. With the application of pressure, the electronic structure of CaKRu$_4$P$_4$ becomes similar to those of the ternary 122-type compounds LaRu$_2$P$_2$ and LaRu$_2$As$_2$. CaKRu$_4$P$_4$ is very likely to be a phonon-mediated medium coupled BCS superconductor. Furthermore, type-I and type-II Dirac fermions can be created and regulated in this system with pressure. The quaternary compound CaKRu$_4$P$_4$ therefore has a potential to be an attractive platform for the study of topological physics and superconductivity.

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Xinlei Zhao, Fengjie Ma, Zhong-Yi Lu. 2021-12-04. First-principles study of the electronic structure of CaKRu$_4$P$_4$. https://doi.org/10.1103/physrevb.104.235105

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