Effect of pressure on the self-hole-doped superconductor RbGd2Fe4As4O2. (13th December 2018)

• Record Type: Journal Article
• Authors: Sun, J P; Wang, Z-C; Liu, Z Y; Xu, S X; Eto, T; Sui, Y; Wang, B S; Uwatoko, Y; Cao, G-H; Cheng, J-G
• Is Part Of: Journal of physics. Volume 31:Number 4(2019)
• Publication Date: 2018-12-13
• Subjects: Fe-based superconductor -- pressure effect -- non Fermi liquid; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aaf0b9
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: RbGd2 Fe4 As4 O2 is a newly discovered self-hole-doped stoichiometric superconductor, which has a hybrid structure with separated double FeAs layers and exhibits a high superconducting transition temperature T c = 35 K. Here, we report the effect of pressure ( P ) on its T c and normal-state transport properties by measuring the temperature dependence of resistivity ρ ( T ) under various pressures up to 14 GPa with a cubic anvil cell apparatus. We found that the T c is suppressed monotonically to ca. 12.5 K upon increasing pressure to 14 GPa with a slope change of T c ( P ) at around 4 GPa. In addition, the low-temperature normal-state ρ ( T ), which is proportional to T n, also evolves gradually from a non-Fermi-liquid with n = 1 at ambient pressure to a Fermi liquid with n = 2 at P ⩾ 4 GPa. Accompanying with the non-Fermi-liquid to Fermi-liquid crossover, the quadratic temperature coefficient of resistivity, which reflects the effective mass of charge carriers, also experiences a significant reduction as commonly observed in the vicinity of a magnetic quantum critical point (QCP). Our results indicate that the stoichiometric RbGd2 Fe4 As4 O2 at ambient pressure might be located near a QCP such that the enhanced critical spin fluctuations lead to high- T c superconductivity. The application of pressure should broaden the electronic bandwidth and weaken the spin fluctuations, and then restore a Fermi-liquid ground state with lower T c .