Observation of Flat Bands and Dirac Cones in a Pyrochlore Lattice Superconductor
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| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866914953976348672 |
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| author | Huang, Jianwei Setty, Chandan Deng, Liangzi You, Jing-Yang Liu, Hongxiong Shao, Sen Oh, Ji Seop Guo, Yucheng Zhang, Yichen Yue, Ziqin Yin, Jia-Xin Hashimoto, Makoto Lu, Donghui Gorovikov, Sergey Dai, Pengcheng Denlinger, Jonathan D. Hasan, M. Zahid Feng, Yuan-Ping Birgeneau, Robert J. Shi, Youguo Chu, Ching-Wu Chang, Guoqing Si, Qimiao Yi, Ming |
| author_facet | Huang, Jianwei Setty, Chandan Deng, Liangzi You, Jing-Yang Liu, Hongxiong Shao, Sen Oh, Ji Seop Guo, Yucheng Zhang, Yichen Yue, Ziqin Yin, Jia-Xin Hashimoto, Makoto Lu, Donghui Gorovikov, Sergey Dai, Pengcheng Denlinger, Jonathan D. Hasan, M. Zahid Feng, Yuan-Ping Birgeneau, Robert J. Shi, Youguo Chu, Ching-Wu Chang, Guoqing Si, Qimiao Yi, Ming |
| contents | Emergent phases often appear when the electronic kinetic energy is comparable to the Coulomb interactions. One approach to seek material systems as hosts of such emergent phases is to realize localization of electronic wavefunctions due to the geometric frustration inherent in the crystal structure, resulting in flat electronic bands. Recently, such efforts have found a wide range of exotic phases in the two-dimensional kagome lattice, including magnetic order, time-reversal symmetry breaking charge order, nematicity, and superconductivity. However, the interlayer coupling of the kagome layers disrupts the destructive interference needed to completely quench the kinetic energy. Here we demonstrate that an interwoven kagome network-a pyrochlore lattice-can host a three dimensional (3D) localization of electron wavefunctions. Meanwhile, the nonsymmorphic symmetry of the pyrochlore lattice guarantees all band crossings at the Brillouin zone X point to be 3D gapless Dirac points, which was predicted theoretically but never yet observed experimentally. Through a combination of angle-resolved photoemission spectroscopy, fundamental lattice model and density functional theory calculations, we investigate the novel electronic structure of a Laves phase superconductor with a pyrochlore sublattice, CeRu$_2$. We observe flat bands originating from both the Ce 4$f$ orbitals as well as from the 3D destructive interference of the Ru 4$d$ orbitals. We further observe the nonsymmorphic symmetry-protected 3D gapless Dirac cones at the X point. Our work establishes the pyrochlore structure as a promising lattice platform to realize and tune novel emergent phases intertwining topology and many-body interactions. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2304_09066 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Observation of Flat Bands and Dirac Cones in a Pyrochlore Lattice Superconductor Huang, Jianwei Setty, Chandan Deng, Liangzi You, Jing-Yang Liu, Hongxiong Shao, Sen Oh, Ji Seop Guo, Yucheng Zhang, Yichen Yue, Ziqin Yin, Jia-Xin Hashimoto, Makoto Lu, Donghui Gorovikov, Sergey Dai, Pengcheng Denlinger, Jonathan D. Hasan, M. Zahid Feng, Yuan-Ping Birgeneau, Robert J. Shi, Youguo Chu, Ching-Wu Chang, Guoqing Si, Qimiao Yi, Ming Strongly Correlated Electrons Materials Science Superconductivity Emergent phases often appear when the electronic kinetic energy is comparable to the Coulomb interactions. One approach to seek material systems as hosts of such emergent phases is to realize localization of electronic wavefunctions due to the geometric frustration inherent in the crystal structure, resulting in flat electronic bands. Recently, such efforts have found a wide range of exotic phases in the two-dimensional kagome lattice, including magnetic order, time-reversal symmetry breaking charge order, nematicity, and superconductivity. However, the interlayer coupling of the kagome layers disrupts the destructive interference needed to completely quench the kinetic energy. Here we demonstrate that an interwoven kagome network-a pyrochlore lattice-can host a three dimensional (3D) localization of electron wavefunctions. Meanwhile, the nonsymmorphic symmetry of the pyrochlore lattice guarantees all band crossings at the Brillouin zone X point to be 3D gapless Dirac points, which was predicted theoretically but never yet observed experimentally. Through a combination of angle-resolved photoemission spectroscopy, fundamental lattice model and density functional theory calculations, we investigate the novel electronic structure of a Laves phase superconductor with a pyrochlore sublattice, CeRu$_2$. We observe flat bands originating from both the Ce 4$f$ orbitals as well as from the 3D destructive interference of the Ru 4$d$ orbitals. We further observe the nonsymmorphic symmetry-protected 3D gapless Dirac cones at the X point. Our work establishes the pyrochlore structure as a promising lattice platform to realize and tune novel emergent phases intertwining topology and many-body interactions. |
| title | Observation of Flat Bands and Dirac Cones in a Pyrochlore Lattice Superconductor |
| topic | Strongly Correlated Electrons Materials Science Superconductivity |
| url | https://arxiv.org/abs/2304.09066 |