Manipulation of gap nodes by uniaxial strain in iron-based superconductors

Abstract

In the iron pnictides and chalcogenides, multiple orbitals participate in the superconducting state, enabling different gap structures to be realized in distinct materials. Here we argue that the spectral weights of these orbitals can in principle be controlled by a tetragonal symmetry-breaking uniaxial strain, due to the enhanced nematic susceptibility of many iron-based superconductors. By investigating multi-orbital microscopic models in the presence of orbital order, we show that not only $T_c$ can be enhanced, but pairs of accidental gap nodes can be annihilated and created in the Fermi surface by an increasing external strain. We explain our results as a mixture of nearly-degenerate superconducting states promoted by strain, and show that the annihilation and creation of nodes can be detected experimentally via anisotropic penetration depth measurements. Our results provide a promising framework to externally control the superconducting properties of iron-based materials.

4 pages + supplementary material, published in in Phys. Rev. Lett

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Cited by in corpus (8)

• Low-energy microscopic models for iron-based superconductors: a review
• Unexpected two-fold symmetric superconductivity in few-layer NbSe${}_2$
• Distinguishing spin-orbit coupling and nematic order in the electronic spectrum of iron-based superconductors
• Anisotropic superconductivity mediated by ferroelectric fluctuations in cubic systems with spin-orbit coupling
• Two distinct superconducting states controlled by orientation of local wrinkles in LiFeAs
• Nematicity and superconductivity: Competition versus cooperation
• Displacement and annihilation of Dirac gap-nodes in d-wave iron-based superconductors
• Structure of the pairing gap from orbital nematic fluctuations