Electron correlation induced orbital selective Lifshitz transition in new hybrid 12442 iron based superconductors
Electron correlation induced orbital selective Lifshitz transition in new hybrid 12442 iron based superconductors
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DOI：
10.1016/j.commatsci.2020.109802
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发表时间：
2020-10-01
影响因子：
3.3
通讯作者：
Ghosh, Haranath
中科院分区：
文献类型：
--
作者：
Ghosh, Abyay;Ghosh, Soumyadeep;Ghosh, Haranath
用密度泛函第一性原理方法对新发现的Aca(2)Fe(4)As(4)F(2)，即12442个铁基化合物(A=K，Rb，Cs)进行了详细的电子结构计算。轨道投影能带结构揭示了这12442个化合物的混合多轨道多能带性质，主要贡献来自Fe-3D轨道。与其他杂化铁基超导体不同，As-4p(Z)轨道在这些化合物中的贡献可以忽略不计。原子半径逐渐增大的碱原子的取代对化合物内部施加化学压力，导致能带结构和态密度的轨道选择性演化。轨道投影费米面揭示了d(x2-y2/z2)和d(xz/yz)轨道衍生FSS的轨道内、带间嵌套条件下的轨道选择性修正。通过GGA+U计算揭示了关联诱导的轨道选择性Lifshitz跃迁。用最大局域Wannier函数与低能密度泛函拟合的紧束缚带结构揭示了最近邻跳跃参数的一个独特特征。与许多铁基化合物相比，d(Z2)的轨道内跃迁大于d(x2-y2)的轨道内跃迁。在这些化合物中，d(Xy)和d(Yz)的轨道跃迁由于碱原子Rb或Cs的取代引起的化学压强的变化而选择性降低。
A systematic detailed electronic structure study of the newly discovered ACa(2)Fe(4)As(4)F(2) 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-4p(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(x2-y2/z2) 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(z2) is larger than intra-orbital hopping in d(x2-y2). 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.