Interband coupling and transport interband scattering in $s_{\pm }$ superconductors

Abstract

A two-band model with repulsive interband coupling and interband {\it transport} (potential) scattering is considered to elucidate their effects on material properties. In agreement with previous work, we find that the bands order parameters ${\Delta }_{1,2}$ differ and the large is at the band with a smaller normal density of states (DOS), $N_{n2}<N_{n1}$. However, the bands energy gaps, as determined by the energy dependence of the DOS, are equal due to scattering. For each temperature, the gaps turn zero at a certain critical interband scattering rate, i.e. for strong enough scattering the model material becomes gappless. In the gapless state, the DOS at the band 2 is close to the normal state value, whereas at the band 1 it has a V-shape with non-zero minimum. When the normal bands DOS' are mismatched, $N_{n1}\ne N_{n2}$, the critical temperature $T_c$ is suppressed even in the absence of interband scattering, $T_c(N_{n1})$ has a dome-like shape. With increasing interband scattering, the London penetration depth at low temperatures evolves from being exponentially flat to the power-law and even to near linear behavior in the gapless state, the latter being easily misinterpreted as caused by order parameter nodes.

References in corpus (9)

• Superfluid density and specific heat within self-consistent scheme for two-band superconductor
• Superfluid density and penetration depth in Fe-pnictides
• Doping evolution of the absolute value of the London penetration depth and superfluid density in single crystals of Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Manifestation of impurity induced s_{+-} -> s_{++} transition: multiband model for dynamical response functions
• London Penetration Depth and Pair Breaking
• Pair breaking due to orbital magnetism in iron-based superconductors
• Effect of weak disorder on the phase competition in iron pnictides
• Universal Scaling Law for the Condensation Energy, U, Across a Broad Range of Superconductor Classes
• Uniform impurity scattering in two-band $s_{\pm }$ and $s_{++}$ superconductors

Cited by in corpus (9)

• Nodeless multiband superconductivity in stoichiometric single crystalline CaKFe${}_4$As${}_4$
• The single- vs. two-gap scenario: the specific heat and the thermodynamic critical field of BeAu superconductor
• Multi-band $s_{++}$ superconductivity in ${\text{V}}_3\text{Si}$ determined from the response to a controlled disorder
• Locking of length scales in two-band superconductors
• Anisotropic superconductivity of niobium based on its response to non-magnetic disorder
• London penetration depth measurements using tunnel diode resonators
• Effect of controlled artificial disorder on the magnetic properties of EuFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$ ferromagnetic superconductor
• Single-band to two-band superconductivity transition in two-dimensional oxide interfaces
• Origin of the dome-shaped superconducting phase diagram in ${\mathrm{SrTiO}}_3$-based interfaces