Enhanced superconductivity of Ba0.5K0.5Fe2As2 under surface potassium dosing. (16th October 2018)

• Record Type: Journal Article
• Authors: Miao, Jin; Niu, Xiaohai; Jiang, Juan; Peng, Rui; Xie, Binping; Chen, Fei; Xu, Haichao; Feng, Donglai
• Is Part Of: Journal of physics. Volume 30:Number 45(2018)
• Publication Date: 2018-10-16
• Subjects: electronic structure -- surface potassium dosing -- ARPES -- iron-based superconductors; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aae423
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: Surface potassium dosing has been proven to be an effective method in tuning the electron doping and enhancing the superconducting transition temperatures in both iron chalcogenides and electron doped iron pnictides. However, it is not clear how surface potassium dosing affects the hole doping and superconductivity in hole doped Fe-based superconductors. Here we performed K-dosing on Ba0.5 K0.5 Fe2 As2, a prototypical hole-doped iron pnictide compound, and explored the electronic structure by in situ angle-resolved photoemission spectroscopy measurements. Starting from the slightly over-doped Ba0.5 K0.5 Fe2 As2, surface K-dosing effectively reduces the hole concentration towards optimal doping and enhances the superconductivity. Intriguingly, the enhancement of superconductivity does not slow down at optimal doping, and the gap further increases with K dosing even when the carrier doping effect is saturated. Meanwhile, the quasiparticle coherence of the inner hole pockets is enhanced by higher K dosing. Our results uncover a novel scattering-reduction effect of K-dosing in Ba1− x K x Fe2 As2, which collaborates with the carrier doping effect and enhances superconductivity.