A Sharp Peak of the Zero-Temperature Penetration Depth at Optimal Composition in BaFe2(As1-xPx)(2)

TitleA Sharp Peak of the Zero-Temperature Penetration Depth at Optimal Composition in BaFe2(As1-xPx)(2)
Publication TypeJournal Article
Year of Publication2012
AuthorsHashimoto K, Cho K, Shibauchi T, Kasahara S, Mizukami Y, Katsumata R, Tsuruhara Y, Terashima T, Ikeda H, Tanatar MA, Kitano H, Salovich N, Giannetta RW, Walmsley P, Carrington A, Prozorov R, Matsuda Y
Journal TitleScience
Volume336
Pages1554-1557
Date Published06
Type of ArticleArticle
ISBN Number0036-8075
Accession NumberWOS:000305507500050
Keywordsbcs, CROSSOVER, high-t-c, QUANTUM CRITICALITY, superconductors
Abstract

In a superconductor, the ratio of the carrier density, n, to its effective mass, m*, is a fundamental property directly reflecting the length scale of the superfluid flow, the London penetration depth, lambda(L). In two-dimensional systems, this ratio n/m* (similar to 1/lambda(2)(L)) determines the effective Fermi temperature, T-F. We report a sharp peak in the x-dependence of lambda(L) at zero temperature in clean samples of BaFe2(As1-xPx)(2) at the optimum composition x = 0.30, where the superconducting transition temperature T-c reaches a maximum of 30 kelvin. This structure may arise from quantum fluctuations associated with a quantum critical point. The ratio of T-c/T-F at x = 0.30 is enhanced, implying a possible crossover toward the Bose-Einstein condensate limit driven by quantum criticality.

URL<Go to ISI>://WOS:000305507500050
DOI10.1126/science.1219821
Alternate JournalScience