Non-trivial band topology and orbital-selective electronic nematicity in a new titanium-based kagome superconductor
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| Main Authors: | , , , , , , , , , , , , , |
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| Format: | Preprint |
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2022
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| _version_ | 1866909324227379200 |
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| author | Hu, Yong Le, Congcong Zhao, Zhen Ma, Junzhang Plumb, Nicholas C. Radovic, Milan Schnyder, Andreas P. Wu, Xianxin Chen, Hui Dong, Xiaoli Hu, Jiangping Yang, Haitao Gao, Hong-Jun Shi, Ming |
| author_facet | Hu, Yong Le, Congcong Zhao, Zhen Ma, Junzhang Plumb, Nicholas C. Radovic, Milan Schnyder, Andreas P. Wu, Xianxin Chen, Hui Dong, Xiaoli Hu, Jiangping Yang, Haitao Gao, Hong-Jun Shi, Ming |
| contents | Electronic nematicity that spontaneously breaks rotational symmetry has been shown as a generic phenomenon in correlated quantum systems including high-temperature superconductors and the AV3Sb5 (A = K, Rb, Cs) family with a kagome network. Identifying the driving force has been a central challenge for understanding nematicity. In iron-based superconductors, the problem is complicated because the spin, orbital and lattice degrees of freedom are intimately coupled. In vanadium-based kagome superconductors AV3Sb5, the electronic nematicity exhibits an intriguing entanglement with the charge density wave order (CDW), making understanding its origin difficult. Recently, a new family of titanium-based kagome superconductors ATi3Bi5 has been synthesized. In sharp contrast to its vanadium-based counterpart, the electronic nematicity occurs in the absence of CDW. ATi3Bi5 provides a new window to explore the mechanism of electronic nematicity and its interplay with the orbital degree of freedom. Here, we combine polarization-dependent angle-resolved photoemission spectroscopy with density functional theory to directly reveal the band topology and orbital characters of the multi-orbital RbTi3Bi5. The promising coexistence of flat bands, type-II Dirac nodal line and nontrivial Z2 topological states is identified in RbTi3Bi5. Remarkably, our study clearly unveils the orbital character change along the G-M and G-K directions, implying a strong intrinsic inter-orbital coupling in the Ti-based kagome metals, reminiscent of iron-based superconductors. Furthermore, doping-dependent measurements directly uncover the orbital-selective features in the kagome bands, which can be well explained by the d-p hybridization. The suggested d-p hybridization, in collaboration with the inter-orbital coupling, could account for the electronic nematicity in ATi3Bi5. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2212_07958 |
| institution | arXiv |
| publishDate | 2022 |
| record_format | arxiv |
| spellingShingle | Non-trivial band topology and orbital-selective electronic nematicity in a new titanium-based kagome superconductor Hu, Yong Le, Congcong Zhao, Zhen Ma, Junzhang Plumb, Nicholas C. Radovic, Milan Schnyder, Andreas P. Wu, Xianxin Chen, Hui Dong, Xiaoli Hu, Jiangping Yang, Haitao Gao, Hong-Jun Shi, Ming Superconductivity Materials Science Strongly Correlated Electrons Electronic nematicity that spontaneously breaks rotational symmetry has been shown as a generic phenomenon in correlated quantum systems including high-temperature superconductors and the AV3Sb5 (A = K, Rb, Cs) family with a kagome network. Identifying the driving force has been a central challenge for understanding nematicity. In iron-based superconductors, the problem is complicated because the spin, orbital and lattice degrees of freedom are intimately coupled. In vanadium-based kagome superconductors AV3Sb5, the electronic nematicity exhibits an intriguing entanglement with the charge density wave order (CDW), making understanding its origin difficult. Recently, a new family of titanium-based kagome superconductors ATi3Bi5 has been synthesized. In sharp contrast to its vanadium-based counterpart, the electronic nematicity occurs in the absence of CDW. ATi3Bi5 provides a new window to explore the mechanism of electronic nematicity and its interplay with the orbital degree of freedom. Here, we combine polarization-dependent angle-resolved photoemission spectroscopy with density functional theory to directly reveal the band topology and orbital characters of the multi-orbital RbTi3Bi5. The promising coexistence of flat bands, type-II Dirac nodal line and nontrivial Z2 topological states is identified in RbTi3Bi5. Remarkably, our study clearly unveils the orbital character change along the G-M and G-K directions, implying a strong intrinsic inter-orbital coupling in the Ti-based kagome metals, reminiscent of iron-based superconductors. Furthermore, doping-dependent measurements directly uncover the orbital-selective features in the kagome bands, which can be well explained by the d-p hybridization. The suggested d-p hybridization, in collaboration with the inter-orbital coupling, could account for the electronic nematicity in ATi3Bi5. |
| title | Non-trivial band topology and orbital-selective electronic nematicity in a new titanium-based kagome superconductor |
| topic | Superconductivity Materials Science Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2212.07958 |