تقرير
Temperature-Dependence of Magnetically-Active Charge Excitations in Magnetite across the Verwey Transition
| العنوان: | Temperature-Dependence of Magnetically-Active Charge Excitations in Magnetite across the Verwey Transition |
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| المؤلفون: | Taguchi, M., Chainani, A., Ueda, S., Matsunami, M., Ishida, Y., Eguchi, R., Tsuda, S., Takata, Y., Yabashi, M., Tamasaku, K., Nishino, Y., Ishikawa, T., Daimon, H., Todo, S., Tanaka, H., Oura, M., Senba, Y., Ohashi, H., Shin, S. |
| المصدر: | Phys. Rev. Lett. 115, 256405 (2015) |
| سنة النشر: | 2015 |
| المجموعة: | Condensed Matter |
| مصطلحات موضوعية: | Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Materials Science |
| الوصف: | We have studied the electronic structure of bulk single crystals and epitaxial films of magnetite Fe$_3$O$_4$. Fe $2p$ core-level spectra show clear differences between hard x-ray (HAX-) and soft x-ray (SX-) photoemission spectroscopy (PES), indicative of surface effects. The bulk-sensitive spectra exhibit temperature ($T$)-dependent charge excitations across the Verwey transition at $T_V$=122 K, which is missing in the surface-sensitive spectra. An extended impurity Anderson model full-multiplet analysis reveals roles of the three distinct Fe-species (A-Fe$^{3+}$, B-Fe$^{2+}$, B-Fe$^{3+}$) below $T_V$ for the Fe $2p$ spectra, and its $T-$dependent evolution. The Fe $2p$ HAXPES spectra show a clear magnetic circular dichroism (MCD) in the metallic phase of magnetized 100-nm-thick films. The model calculations also reproduce the MCD and identify the magnetically distinct sites associated with the charge excitations. Valence band HAXPES shows finite density of states at $E_F$ for the polaronic metal with remnant order above $T_V$, and a clear gap formation below $T_V$. The results indicate that the Verwey transition is driven by changes in the strongly correlated and magnetically active B-Fe$^{2+}$ and B-Fe$^{3+}$ electronic states, consistent with resistivity and bulk-sensitive optical spectra. Comment: 5 pages, 4 figures Accepted in Physical Review Letters |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1103/PhysRevLett.115.256405 |
| URL الوصول: | http://arxiv.org/abs/1504.05316 |
| رقم الأكسشن: | edsarx.1504.05316 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1103/PhysRevLett.115.256405 |
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