Point-contact spectroscopic studies on normal and superconducting AFe(2)As(2)-type iron pnictide single crystals

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	Point-contact spectroscopic studies on normal and superconducting AFe(2)As(2)-type iron pnictide single crystals
	Lu, X ; Park, WK ; Yuan, HQ ; Chen, GF ; Luo, GL ; Wang, NL ; Sefat, AS ; McGuire, MA ; Jin, R ; Sales, BC ; Mandrus, D ; Gillett, J ; Sebastian, SE ; Greene, LH
刊名	SUPERCONDUCTOR SCIENCE & TECHNOLOGY
	2010
卷号	23 期号:5
关键词	RESOLVED PHOTOEMISSION-SPECTROSCOPY GAPS BA0.6K0.4FE2AS2 SYMMETRY SURFACE
ISSN号	0953-2048
通讯作者	Lu, X (reprint author), Univ Illinois, Dept Phys, Urbana, IL 61801 USA.
中文摘要	Point-contact Andreev reflection spectroscopy is applied to investigate the gap structure in iron pnictide single-crystal superconductors of the AFe(2)As(2) (A = Ba, Sr) family ('Fe-122'). The observed point-contact junction conductance curves, G(V), can be divided into two categories: one where Andreev reflection is present for both (Ba0.6K0.4) Fe2As2 and Ba(Fe0.9Co0.1)(2)As-2, and the other with a V-2/3 background conductance universally observed, extending even up to 100 meV for Sr0.6Na0.4Fe2As2 and Sr(Fe0.9Co0.1)(2)As-2. The latter is also observed in point-contact junctions on the nonsuperconducting parent compound BaFe2As2 and superconducting (Ba0.6K0.4)Fe2As2 crystals. Mesoscopic phase-separated coexistence of magnetic and superconducting orders is considered to explain distinct behaviors in the superconducting samples. For Ba0.6K0.4Fe2As2, double peaks due to Andreev reflection with a strongly sloping background are frequently observed for point contacts on freshly cleaved c-axis surfaces. If normalized using a background baseline and analyzed using the Blonder-Tinkham-Klapwijk model, the data show a gap size of similar to 3.0-4.0 meV with 2 Delta(0)/k(B)T(c)similar to 2.0-2.6, consistent with the smaller gap size reported for the LnFeAsO family ('Fe-1111'). For the Ba(Fe0.9Co0.1)(2)As-2, the G(V) curves typically display a zero-bias conductance peak.
收录类别	SCI
资助信息	US DoE through the Frederick Seitz Materials Research Laboratory [DEFG02-07ER46453]; Center for Micro-analysis of Materials at UIUC; NSF [DMR 07-06013]; National Science Foundation of China [10874146, 10934005]; National Basic Research Program of China [2009CB929104]; Zhejiang Natural Science Foundation [ZJNSF R0690113]; Division of Materials Sciences and Engineering, Office of Basic Energy Sciences, DOE
语种	英语
公开日期	2013-09-24
内容类型	期刊论文
源URL	[http://ir.iphy.ac.cn/handle/311004/51076]
专题	物理研究所_物理所公开发表论文_物理所公开发表论文_期刊论文
推荐引用方式 GB/T 7714	Lu, X,Park, WK,Yuan, HQ,et al. Point-contact spectroscopic studies on normal and superconducting AFe(2)As(2)-type iron pnictide single crystals[J]. SUPERCONDUCTOR SCIENCE & TECHNOLOGY,2010,23(5).
APA	Lu, X.,Park, WK.,Yuan, HQ.,Chen, GF.,Luo, GL.,...&Greene, LH.(2010).Point-contact spectroscopic studies on normal and superconducting AFe(2)As(2)-type iron pnictide single crystals.SUPERCONDUCTOR SCIENCE & TECHNOLOGY,23(5).
MLA	Lu, X,et al."Point-contact spectroscopic studies on normal and superconducting AFe(2)As(2)-type iron pnictide single crystals".SUPERCONDUCTOR SCIENCE & TECHNOLOGY 23.5(2010).