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

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

Publication Type | Journal Article |

Year of Publication | 2012 |

Authors | Hashimoto 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 Title | Science |

Volume | 336 |

Pages | 1554-1557 |

Date Published | 06 |

Type of Article | Article |

ISBN Number | 0036-8075 |

Accession Number | WOS:000305507500050 |

Keywords | bcs, 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 |

DOI | 10.1126/science.1219821 |

Alternate Journal | Science |