Critical point of the transition between $s_{\pm }$ and $s_{++}$ states of a two-band superconductor with nonmagnetic impurities

Abstract

Behavior of the Grand thermodynamic potential along with its derivatives, entropy and specific heat, is considered within a two-band model of an unconventional $s_{\pm }$ superconductor with nonmagnetic impurities. The transition $s_{\pm }\to s_{++}$ is shown to be a smooth crossover at high temperatures, while it becomes the first order phase transition at low temperatures. Thus, on a phase diagram `temperature'-`impurity scattering rate' there appears to be a critical end point. Temperature at which the behavior of the transition is changed is maximal in the Born limit and tends to zero away from the limit, which points out to the possible realization of a quantum phase transition.

arXiv comment7 pages, 4 figures

References in corpus (18)

• Gap symmetry and structure of Fe-based superconductors
• Magnetism and Charge Dynamics in Iron Pnictides
• High - Temperature Superconductivity in Iron Based Layered Compounds
• Using Gap Symmetry and Structure to Reveal the Pairing Mechanism in Fe-based Superconductors
• Disorder induced transition between s_+- and s_++ states in two-band superconductors
• Impurities in multiband superconductors
• Iron Based Superconductors: Pnictides versus Chalcogenides
• Unexpected impact of magnetic disorder on multiband superconductivity
• Interplay of nematic and magnetic orders in FeSe under pressure
• Analysis of spin density wave conductivity spectra of iron pnictides in the framework of density functional theory
• Anomalous proximity effects at the interface of s and s+- superconductors
• Phase diagram of dirty two-band superconductors and observability of impurity-induced $s+is$ state
• Inter-orbital nematicity and the origin of a single electron Fermi pocket in FeSe
• Strain-tunable metamagnetic critical endpoint in Mott insulating rare-earth titanates
• Details of the disorder-induced transition between $s_{\pm }$ and $s_{++}$ states in two-band model for Fe-based superconductors
• Temperature-dependent $s_{\pm }\leftrightarrow s_{++}$ transitions in the multiband model for Fe-based superconductors with impurities
• Decisive proofs of the $s_{\pm }\to s_{++}$ transition in the temperature dependence of the magnetic penetration depth
• Thermodynamics of $s_{\pm }-to-s_{++}$ transition in iron pnictides in the vicinity of the Born limit