Unified picture of the doping dependence of superconducting transition temperatures in alkali metal/ammonia intercalated FeSe

Abstract

In the recently synthesized Li${}_x$(NH${}_2$)${}_y$(NH${}_3$)${}_z$Fe${}_2$Se${}_2$ family of iron chalcogenides a molecular spacer consisting of lithium ions, lithium amide and ammonia separates layers of FeSe. It has been shown that upon variation of the chemical composition of the spacer layer, superconducting transition temperatures can reach $T_c\sim 44\mathrm{K}$, but the relative importance of the layer separation and effective doping to the $T_c$ enhancement is currently unclear. Using state of the art band structure unfolding techniques, we construct eight-orbital models from ab-initio density functional theory calculations for these materials. Within an RPA spin-fluctuation approach, we show that the electron doping enhances the superconducting pairing, which is of $s_{\pm }$-symmetry and explain the experimentally observed limit to $T_c$ in the molecular spacer intercalated FeSe class of materials.

References in corpus (11)

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• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• d-wave pairing from spin fluctuations in the KxFe{2-y}Se2 superconductors
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• Synthesis and post-annealing effects of alkaline-metal-ethylenediamine-intercalated superconductors Ax(C2H8N2)yFe2-zSe2 (A = Li, Na) with Tc = 45 K
• Angle-resolved photoemission evidence of s-wave superconducting gap in KxFe2-ySe2 superconductor
• Unfolding of the electronic structure through the induced representations of space groups: Application to Fe-based superconductors

Cited by in corpus (12)

• Iron-Based Superconductors: current status of materials and pairing mechanism
• Extreme anisotropy and anomalous transport properties of heavily electron doped Lix(NH3)yFe2Se2 single crystals
• Interplay of nematic and magnetic orders in FeSe under pressure
• Origin of the superconducting state in the collapsed tetragonal phase of KFe2As2
• Spin resonance in the superconducting state of Li${}_{1-x}$Fe${}_x$ODFe${}_{1-y}$Se observed by neutron spectroscopy
• Low-energy spin excitations in Li(0.8)Fe(0.2)ODFeSe superconductor studied with inelastic neutron scattering
• New Alkali-Metal- and 2-Phenethylamine-Intercalated Superconductors $A_x$(C${}_8$H${}_{11}$N)${}_y$Fe${}_{1-z}$Se ($A$ = Li, Na) with the Largest Interlayer Spacings and $T_{\mathrm{c}}$ $\sim$ 40 K
• Origin of the non-monotonic variance of Tc in the 1111 iron based superconductors with isovalent doping
• Basic electronic properties of iron selenide under variation of structural parameters
• Non-trivial role of interlayer cation states in iron-based superconductors
• Superconductivity and Intercalation Statein the Lithium-Hexamethylenediamine-Intercalated Superconductor Li${}_x$(C${}_6$H${}_{16}$N${}_2$)${}_y$Fe${}_{2-z}$Se${}_2$: Dependence on the Intercalation Temperature and Lithium Content
• Two new parent compounds for FeSe-based superconducting phases