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Electron correlation induced orbital selective Lifshitz transition in new hybrid 12442 iron based superconductors
Computational Materials Science ( IF 3.1 ) Pub Date : 2020-10-01 , DOI: 10.1016/j.commatsci.2020.109802
Abyay Ghosh , Soumyadeep Ghosh , Haranath Ghosh

Abstract A systematic detailed electronic structure study of the newly discovered ACa2Fe4As4F2 i.e., 12442 iron based compounds (where A = K, Rb, Cs) within density functional theory (DFT) based first principles calculations is presented. The orbital projected band structures reveal mixed multi-orbital multi-band nature of the 12442 compounds having contributions mostly from Fe-3d orbitals. Unlike other hybrid iron based superconductors, contribution of As-4 p z orbital is negligible in these compounds. Substitution of alkali atoms of gradually higher atomic radius exert chemical pressure inside the compound and induce orbital selective evolution of band structure as well as density of states. Orbital projected Fermi surfaces divulge orbital selective modification in intra orbital, inter-band nesting condition of the d x 2 - y 2 / z 2 and d xz / yz orbital derived FSs. Correlation induced orbital selective Lifshitz transition is revealed through GGA+U calculations. The tight binding band structure fitted with low energy DFT bands using maximally localized Wannier functions divulge a unique feature of the nearest neighbor hopping parameter. In contrast to many iron based compounds, intra-orbital hopping in d z 2 is larger than intra-orbital hopping in d x 2 - y 2 . Orbital selective decrease in intra-orbital hopping of d xy and d yz due to change in chemical pressure induced by substitution of alkali atoms Rb or Cs is revealed in these compounds.

中文翻译:

新型杂化 12442 铁基超导体中的电子相关诱导轨道选择性 Lifshitz 跃迁

摘要 对新发现的 ACa2Fe4As4F2 即 12442 种铁基化合物(其中 A = K、Rb、Cs)在基于第一性原理计算的密度泛函理论 (DFT) 中进行了系统详细的电子结构研究。轨道投影带结构揭示了 12442 化合物的混合多轨道多带性质,其贡献主要来自 Fe-3d 轨道。与其他杂化铁基超导体不同,这些化合物中 As-4 pz 轨道的贡献可以忽略不计。逐渐增大原子半径的碱原子的取代在化合物内部施加化学压力并诱导能带结构和态密度的轨道选择性演化。轨道投影费米表面揭示轨道内轨道选择性修改,dx 2 - y 2 / z 2 和d xz / yz 轨道导出的FS 的带间嵌套条件。通过 GGA+U 计算揭示了相关性诱导的轨道选择性 Lifshitz 跃迁。使用最大局部万尼尔函数配备低能量 DFT 带的紧束缚带结构揭示了最近邻跳跃参数的独特特征。与许多铁基化合物相比,dz 2 中的轨道内跳跃大于dx 2 -y 2 中的轨道内跳跃。在这些化合物中揭示了由于由碱原子 Rb 或 Cs 取代引起的化学压力变化导致 d xy 和 d yz 轨道内跳跃的轨道选择性降低。使用最大局部万尼尔函数配备低能量 DFT 带的紧束缚带结构揭示了最近邻跳跃参数的独特特征。与许多铁基化合物相比,dz 2 中的轨道内跳跃大于dx 2 -y 2 中的轨道内跳跃。在这些化合物中揭示了由于由碱原子 Rb 或 Cs 取代引起的化学压力变化导致 d xy 和 d yz 轨道内跳跃的轨道选择性降低。使用最大局部万尼尔函数配备低能量 DFT 带的紧束缚带结构揭示了最近邻跳跃参数的独特特征。与许多铁基化合物相比,dz 2 中的轨道内跳跃大于dx 2 -y 2 中的轨道内跳跃。在这些化合物中揭示了由于由碱原子 Rb 或 Cs 取代引起的化学压力变化导致 d xy 和 d yz 轨道内跳跃的轨道选择性降低。
更新日期:2020-10-01
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