| 摘要: |
| 探求具较高超导转变温度的材料并揭示高温超导机理在凝聚态物理领域具有持续热度。超导转变温度Tc作为重要参数，探索它与各种宏观、微观因素的关系机制有助于多角度理解高温超导机理，从而寻找提高Tc的可能途径。受铜氧化合物超导体和铁基超导体块层结构模型的启发，我们在1144交生型铁基超导材料AkAeFe4As4（Ak=K,Rb,Cs;Ae=Ca,Eu)体系中基于块层模型计算了块间相互作用能并探求其与Tc关系，发现块间结合能增加，Tc减小；反之块间结合能减小，Tc增加。这可能是块间相互作用能影响了块体间的电荷转移，导致了两块间载流子数量的变化。进一步通过第一性原理计算其电子结构，发现Fe 3d的能带结构特别是d_(z^2 )轨道对电荷转移的贡献最大，说明沿Z方向AkAeFe4As4存在很强的耦合作用，因而块间相互作用能与Tc强关联。此关系的发现为进一步理解高温超导电性机理和提高超导转变温度Tc提供了一种新思路。 |
| 关键词: 块层模型, 交生型铁基超导体, 块间结合能, 超导转变温度Tc |
| DOI： |
| 投稿时间：2024-02-01修订日期：2024-06-30 |
| 基金项目: |
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| Study on block-layer model for intergrowth structures of 1144 type iron-based superconductor AkAeFe4As4 (Ak=K, Rb, Cs; Ae=Ca, Eu) |
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Zhang Li, Zhou Hanqi, Bian jia nian
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| (China Jiliang University) |
| Abstract: |
| To explore the materials with higher superconducting transition temperature and reveal that the mechanism of high temperature superconductivity has sustained heat in the field of condensed matter physics.The superconducting transition temperature Tc is an important parameter. Exploring the relationship between Tc and various macro and micro factors is helpful to understand the mechanism of high temperature superconductivity from multiple perspectives, so as to find a possible way to improve Tc. Inspired by the block layer structure model of copper oxide superconductors and iron-based superconductors,we calculated the interaction energy between blocks based on the block layer model for intergrowth structures of 1144 type iron-based superconductor AkAeFe4As4(Ak=K，Rb，Cs；Ae=Ca，Eu) system an explored its relationship with Tc. We found that the binding energy between blocks increased and Tc decreased; On the contrary, the binding energy between blocks decreases and Tc increases. It may be that the interaction energy between blocks affects the charge transfer between blocks, resulting in the change of the number of carriers between two blocks. Further, we calculated electronic structure by first principles, and found that the energy band structure of Fe-3d, especially the d_(z^2 ) orbital, contributed the most to the charge transfer when the spin was down, indicating that there was a strong coupling effect in AkAeFe4As4 along the Z direction, so the interaction energy between blocks was strongly correlated with Tc. The discovery of this relationship provides a new idea for further understanding the mechanism of high temperature superconductivity and improving the superconducting transition temperature Tc. |
| Key words: Block layer model, Intergrowth iron-based superconductor, Binding energy between blocks,Superconducting transition temperature |