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作者孙瑞锦,金士锋,邓俊,郝木难,赵琳琳,范晓,孙晓宁,郭建刚,谷林（2019）在《Crystal structures and sign reversal Hall resistivities in iron-based superconductors Lix(C3H10N2)0.32FeSe（0.15 <x< 0.4）》一文中研究指出：Heavy electron-doped FeSe-derived materials have attracted attention due to their uncommon electronic structures with only ‘electron pockets’, and they are different from other iron-based superconductors. Here, we report the crystal structures, superconductivities and normal state properties of two new Li-doped FeSe-based materials, i.e.,Li0.15(C3H10N2)0.32 FeSe（P-4） and Lix(C3H10N2)0.32 FeSe（P4/nmm, 0.25 < x < 0.4） with superconducting transition temperatures ranging from 40 K to 46 K. The determined crystal structures reveal a coupling between Li concentration and the orientation of 1,3-diaminopropane molecules within the largely expanded FeSe layers. Superconducting fluctuations appear in the resistivity of the two superconductors and are fitted in terms of the quasi two-dimensional（2 D） Lawrence–Doniach model. The existence of a crossing point and scaling behavior in the T-dependence of diamagnetic response also suggests that the two superconductors belong to the quasi-2 D system. Interestingly, with the increase of temperature, a sign of Hall coefficient（RH） reversing from negative to positive is observed at ～185 K in both phases, suggesting that‘hole pockets’ emerge in these electron-doped FeSe materials. First principle calculations indicate that the increase in FeSe layer distance will lift up a ‘hole band’ associated with dx2-y2 character and increase the hole carriers. Our findings suggest that the increase in two dimensionalities may lead to the sign-reversal Hall resistivity in Lix(C3H10N2)0.32 FeSe at high temperature.
Abstract
Heavy electron-doped FeSe-derived materials have attracted attention due to their uncommon electronic structures with only ‘electron pockets’, and they are different from other iron-based superconductors. Here, we report the crystal structures, superconductivities and normal state properties of two new Li-doped FeSe-based materials, i.e.,Li0.15(C3H10N2)0.32 FeSe（P-4） and Lix(C3H10N2)0.32 FeSe（P4/nmm, 0.25 < x < 0.4） with superconducting transition temperatures ranging from 40 K to 46 K. The determined crystal structures reveal a coupling between Li concentration and the orientation of 1,3-diaminopropane molecules within the largely expanded FeSe layers. Superconducting fluctuations appear in the resistivity of the two superconductors and are fitted in terms of the quasi two-dimensional（2 D） Lawrence–Doniach model. The existence of a crossing point and scaling behavior in the T-dependence of diamagnetic response also suggests that the two superconductors belong to the quasi-2 D system. Interestingly, with the increase of temperature, a sign of Hall coefficient（RH） reversing from negative to positive is observed at ～185 K in both phases, suggesting that‘hole pockets’ emerge in these electron-doped FeSe materials. First principle calculations indicate that the increase in FeSe layer distance will lift up a ‘hole band’ associated with dx2-y2 character and increase the hole carriers. Our findings suggest that the increase in two dimensionalities may lead to the sign-reversal Hall resistivity in Lix(C3H10N2)0.32 FeSe at high temperature.
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论文作者分别是来自Chinese Physics B的孙瑞锦,金士锋,邓俊,郝木难,赵琳琳,范晓,孙晓宁,郭建刚,谷林，发表于刊物Chinese Physics B2019年06期论文，是一篇关于,Chinese Physics B2019年06期论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自Chinese Physics B2019年06期论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。