Modulation of pairing symmetry with bond disorder in unconventional superconductors

Yao-Tai Kang, Wei-Feng Tsai, and Dao-Xin Yao
Phys. Rev. B 95, 134513 – Published 20 April 2017

Abstract

We study a two-orbital tJ1J2 model, originally developed to describe iron-based superconductors at low energies, in the presence of bond disorder (via next-nearest-neighbor J2-bond dilution). By using the Bogoliubov–de Gennes approach, we self-consistently calculate the local pairing amplitudes and the corresponding density of states, which demonstrate a change of dominant pairing symmetry from s± wave to d wave when increasing disorder strength as long as J1J2. Moreover, the combined pairing interaction and strong bond disorder lead to the formation of s±-wave “islands” with length scale of the superconducting coherence length embedded in a d-wave “sea.” This picture is further complemented by the disorder-averaged pair-pair correlation functions, distinct from the case with potential disorder, where the “sea” is insulating. Due to this inevitable formation of spatial inhomogeneity, the superconducting Tc determined by the superfluid density ρs(T) obviously deviates from the value predicted by the conventional Abrikosov-Gorkov theory, where the pairing amplitudes are viewed as uniformly suppressed as the disorder increases.

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  • Received 12 January 2017
  • Revised 31 March 2017

DOI:https://doi.org/10.1103/PhysRevB.95.134513

©2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Yao-Tai Kang1, Wei-Feng Tsai2,1,*, and Dao-Xin Yao1,†

  • 1State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
  • 2Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan

  • *weifengt@gmail.com
  • yaodaox@mail.sysu.edu.cn

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Issue

Vol. 95, Iss. 13 — 1 April 2017

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