Three-dimensional spin susceptibility in Ba$_{0.75}$K$_{0.25}$Fe$_{2}$As$_{2}$: Out-of-plane modulation revealed by neutron spectroscopy and theoretical modeling
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| Autores principales: | , , , , , , |
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| Formato: | Preprint |
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2024
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| author | Murai, Naoki Suzuki, Katsuhiro Nakajima, Masamichi Kofu, Maiko Ohira-Kawamura, Seiko Inamura, Yasuhiro Kajimoto, Ryoichi |
| author_facet | Murai, Naoki Suzuki, Katsuhiro Nakajima, Masamichi Kofu, Maiko Ohira-Kawamura, Seiko Inamura, Yasuhiro Kajimoto, Ryoichi |
| contents | We present a combined experimental and theoretical investigation of the spin dynamics in the iron-based superconductor Ba$_{0.75}$K$_{0.25}$Fe$_2$As$_2$. Time-of-flight inelastic neutron scattering measurements reveal the three-dimensional (3D) nature of the spin fluctuations, manifested as out-of-plane modulations of the low-energy magnetic intensity. As the energy increases, this 3D-like modulation gradually fades away, leading to a more two-dimensional (2D) profile -- a clear signature of a 3D-to-2D crossover in the spin dynamics. By incorporating a realistic 3D electronic band structure derived from density functional theory (DFT), we reproduce the experimentally observed features of the spin susceptibility, including the pronounced out-of-plane modulation at low energies and its gradual evolution into a more 2D character at higher energies. The calculated susceptibility exhibits a peak at the experimental ordering wavevector $\mathbf{q}_{\mathrm{AFM}} = (0.5, 0.5, 1)$, demonstrating that the DFT-derived 3D model accurately captures the tendency toward out-of-plane antiferromagnetic (AFM) order. Notably, electronic states away from the Fermi level play a crucial role in shaping the susceptibility peak at $\mathbf{q}_{\mathrm{AFM}}$, highlighting the limitations of the Fermi surface nesting picture in explaining the out-of-plane AFM instability. The demonstrated agreement between experiment and theory serves as a benchmark for validating the DFT-derived model as a realistic description of the material-specific electronic structure. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2412_16870 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Three-dimensional spin susceptibility in Ba$_{0.75}$K$_{0.25}$Fe$_{2}$As$_{2}$: Out-of-plane modulation revealed by neutron spectroscopy and theoretical modeling Murai, Naoki Suzuki, Katsuhiro Nakajima, Masamichi Kofu, Maiko Ohira-Kawamura, Seiko Inamura, Yasuhiro Kajimoto, Ryoichi Superconductivity We present a combined experimental and theoretical investigation of the spin dynamics in the iron-based superconductor Ba$_{0.75}$K$_{0.25}$Fe$_2$As$_2$. Time-of-flight inelastic neutron scattering measurements reveal the three-dimensional (3D) nature of the spin fluctuations, manifested as out-of-plane modulations of the low-energy magnetic intensity. As the energy increases, this 3D-like modulation gradually fades away, leading to a more two-dimensional (2D) profile -- a clear signature of a 3D-to-2D crossover in the spin dynamics. By incorporating a realistic 3D electronic band structure derived from density functional theory (DFT), we reproduce the experimentally observed features of the spin susceptibility, including the pronounced out-of-plane modulation at low energies and its gradual evolution into a more 2D character at higher energies. The calculated susceptibility exhibits a peak at the experimental ordering wavevector $\mathbf{q}_{\mathrm{AFM}} = (0.5, 0.5, 1)$, demonstrating that the DFT-derived 3D model accurately captures the tendency toward out-of-plane antiferromagnetic (AFM) order. Notably, electronic states away from the Fermi level play a crucial role in shaping the susceptibility peak at $\mathbf{q}_{\mathrm{AFM}}$, highlighting the limitations of the Fermi surface nesting picture in explaining the out-of-plane AFM instability. The demonstrated agreement between experiment and theory serves as a benchmark for validating the DFT-derived model as a realistic description of the material-specific electronic structure. |
| title | Three-dimensional spin susceptibility in Ba$_{0.75}$K$_{0.25}$Fe$_{2}$As$_{2}$: Out-of-plane modulation revealed by neutron spectroscopy and theoretical modeling |
| topic | Superconductivity |
| url | https://arxiv.org/abs/2412.16870 |