تقرير
Itinerant ferromagnetism and intrinsic anomalous Hall effect in amorphous iron-germanium
| العنوان: | Itinerant ferromagnetism and intrinsic anomalous Hall effect in amorphous iron-germanium |
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| المؤلفون: | Bouma, D. S., Chen, Z., Zhang, B., Bruni, F., Flatté, M. E., Streubel, R., Wang, L. -W., Wu, R. Q., Hellman, F. |
| المصدر: | Phys. Rev. B 101, 014402 (2020) |
| سنة النشر: | 2019 |
| المجموعة: | Condensed Matter |
| مصطلحات موضوعية: | Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science |
| الوصف: | The amorphous iron-germanium system ($a$-Fe$_x$Ge$_{1-x}$) lacks long-range structural order and hence lacks a meaningful Brillouin zone. The magnetization of \aFeGe is well explained by the Stoner model for Fe concentrations $x$ above the onset of magnetic order around $x=0.4$, indicating that the local order of the amorphous structure preserves the spin-split density of states of the Fe-$3d$ states sufficiently to polarize the electronic structure despite $\mathbf{k}$ being a bad quantum number. Measurements reveal an enhanced anomalous Hall resistivity $\rho_{xy}^{\mathrm{AH}}$ relative to crystalline FeGe; this $\rho_{xy}^{\mathrm{AH}}$ is compared to density functional theory calculations of the anomalous Hall conductivity to resolve its underlying mechanisms. The intrinsic mechanism, typically understood as the Berry curvature integrated over occupied $\mathbf{k}$-states but shown here to be equivalent to the density of curvature integrated over occupied energies in aperiodic materials, dominates the anomalous Hall conductivity of $a$-Fe$_x$Ge$_{1-x}$ ($0.38 \leq x \leq 0.61$). The density of curvature is the sum of spin-orbit correlations of local orbital states and can hence be calculated with no reference to $\mathbf{k}$-space. This result and the accompanying Stoner-like model for the intrinsic anomalous Hall conductivity establish a unified understanding of the underlying physics of the anomalous Hall effect in both crystalline and disordered systems. Comment: 11 pages, 10 figures |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1103/PhysRevB.101.014402 |
| الوصول الحر: | http://arxiv.org/abs/1908.06055Test |
| رقم الانضمام: | edsarx.1908.06055 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1103/PhysRevB.101.014402 |
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