Ultrasound evidence for multicomponent superconducting order parameter in Ba1−xKxFe2As2 with electron quadrupling phase
Year: 2025
Type: article
Abstract: Experiments have pointed to the formation of the electron quadrupling condensate in Ba 1− x K x Fe 2 As 2 at x ~ 0.8. The state spontaneously breaks time-reversal symmetry and is sandwiched between two critical points, separating it from the broken time-reversal symmetry (BTRS) superconducting state at $${T}_{{\rm{c}}}^{U(1)}$$ T c U ( 1 ) and a normal-metal state at $${T}_{{\rm{c}}}^{{\rm{Z2}}}$$ T c Z2 . We report a theory of the acoustic effects spectroscopy of systems with an electron quadrupling phase based on ultrasound-velocity measurements. We show that the experimental results are consistent with BTRS superconductivity at x ~ 0.8, fulfilling the necessary condition for the formation of electron quadrupling in Ba 1− x K x Fe 2 As 2 . We provide the theoretical basis and the experimental strategy to study the order parameter symmetry of emerging quadrupling condensates in superconductors.
Source: npj Quantum Materials
Institutions: KTH Royal Institute of Technology, Shanghai Jiao Tong University, Technische Universität Dresden, Leibniz Institute for Solid State and Materials Research, Superconducting and other Innovative Materials and Devices Institute, National Research Council, University of Genoa, Helmholtz-Zentrum Dresden-Rossendorf, Complexity, Topology and Dynamics in Quantum Matter, Dresden High Magnetic Field Laboratory
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,890
OpenAlex ID: W4416718708