تقرير
Spin dynamics in itinerant antiferromagnet ${\rm\bf SrCr_2As_2}$
| العنوان: | Spin dynamics in itinerant antiferromagnet ${\rm\bf SrCr_2As_2}$ |
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| المؤلفون: | Ning, Zhenhua, Das, Pinaki, Lee, Y., Sangeetha, N. S., Abernathy, D. L., Johnston, D. C., McQueeney, R. J., Vaknin, D., Ke, Liqin |
| سنة النشر: | 2024 |
| المجموعة: | Condensed Matter |
| مصطلحات موضوعية: | Condensed Matter - Superconductivity, Condensed Matter - Materials Science |
| الوصف: | SrCr$_2$As$_2$ is an itinerant antiferromagnet in the same structural family as the SrFe2As2 high-temperature superconductors. We report our calculations of exchange coupling parameters $J_{ij}$ for SrCr$_2$As$_2$ using a static linear-response method based on first-principles electronic structure calculations. We find that the dominant nearest neighbor exchange coupling $J_{\rm{1}} > 0$ is antiferromagnetic whereas the next-nearest neighbor interaction $J_{\rm{2}} < 0$ is ferromagnetic with $J_{\rm{2}}$/$J_{\rm{1}}$~=~$-0.68$, reinforcing the checkerboard in-plane structure. Thus, unlike other transition-metal arsenides based on Mn, Fe, or Co, we find no competing magnetic interactions in SrCr$_2$As$_2$, which aligns with experimental findings. Moreover, the orbital resolution of exchange interactions shows that $J_1$ and $J_2$ are dominated by direct exchange mediated by the Cr $d$ orbitals. To validate the calculations we conduct inelastic neutron-scattering measurements on powder samples that show steeply dispersive magnetic excitations arising from the magnetic $\Gamma$ points and persisting up to energies of at least 175 meV. The spin-wave spectra are then modeled using the Heisenberg Hamiltonian with the theoretically calculated exchange couplings. The calculated neutron scattering spectra are in good agreement with the experimental data. Comment: 9 pages, 6 figures |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/2408.05583 |
| رقم الأكسشن: | edsarx.2408.05583 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |