Argonne National Laboratory

Article | Materials Science

Quantum FFLO state in clean superconductors
In a study published in Physical Review X, researchers found that in clean superconductors under strong magnetic field, quantum effects can generate a nonuniform state, in which strength of superconductivity is periodically modulated.
The dependence of the critical Maki’s parameter αC on μ/tz.
The dependence of the critical Maki’s parameter αC on μ/tz. Note that at negative μ this parameter approaches the known value for the isotropic case αC≈1.8.

Scientific Achievement

We show that in clean superconductors under strong magnetic field, quantum effects can generate a nonuniform state, in which strength of superconductivity is periodically modulated along the field direction.

Significance and Impact

This work demonstrates that FFLO states exist even in materials with small Zeeman energy, thereby revising the accepted picture of the true ground state of very clean superconductors in high magnetic fields.

Research Details

  • We investigated the influence of Landau quantization on the superconducting instability for a pure layered superconductor in the magnetic field directed perpendicular to the layers.
  • We found that the quantization corrections to the Cooper pairing promote the formation of the FFLO state at the temperature proportional to the ratio of the superconducting transition temperature squared and the Fermi energy.

DOE: 10.1103/PhysRevX.9.021025

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