2020/11/30 by Carsten Timm, P. M. R. Brydon, D. F. Agterberg +1
Materials Science · Mathematics · Physics and Astronomy · #Condensed matter physics #Cooper pair #Coupling (piping) #Fermi Gamma-ray Space Telescope #Instability #Iron-based superconductors research #Lattice (music) #Logarithm #Mathematical analysis #Mathematics #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Quasiparticle #Superconductivity #Superconductivity in MgB2 and Alloys #Symmetry breaking #Theoretical physics #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.103.024521
published as Phys. Rev. B 103, 024521 (2021) · 16+ pages, 4 figures
arxiv created 2021/01/21 · openalex publication_date 2021/01/21 · arxiv updated 2021/01/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Centrosymmetric multiband superconductors which break time-reversal symmetry generically have two-dimensional nodes, i.e., Fermi surfaces of Bogoliubov quasiparticles. We show that the coupling of the electrons to the lattice always leads to a weak-coupling instability of such a state toward spontaneous breaking of inversion symmetry at low temperatures. This instability is driven by a Cooper logarithm in the internal energy but the order parameter is not superconducting but distortional. We present a comprehensive symmetry analysis and introduce a measure that allows us to compare the strengths of competing distortional instabilities. Moreover, we discuss the instability using an effective single-band model. This framework reveals a duality mapping of the effective model which maps the distortional order parameter onto a superconducting one, providing a natural explanation for the Cooper logarithm and the weak-coupling nature of the instability. Finally, we consider the possibility of a pair-density wave state when inversion symmetry is broken. We find that it can indeed exist but does not affect the instability itself.