Fulde–Ferrell–Larkin–Ovchinnikov superconducting diode effect in altermagnetic CrSb

Investigate whether the finite-momentum Fulde–Ferrell–Larkin–Ovchinnikov state enabled by the simultaneous breaking of space-inversion and time-reversal symmetries in altermagnetic CrSb produces a superconducting diode effect.

Background

The paper notes that altermagnetic CrSb simultaneously breaks space-inversion and time-reversal symmetries, making a finite-momentum Fulde–Ferrell–Larkin–Ovchinnikov state theoretically feasible. Such a state could generate nonreciprocal superconducting transport, but the associated superconducting diode effect is identified as unexplored rather than demonstrated in the reported Josephson junction experiments.

This unresolved issue is motivated by the observed long-distance Josephson supercurrent and the proposed role of strain-induced spin–orbit coupling in converting singlet correlations into equal-spin triplet correlations. Establishing whether the same altermagnetic and strain-related mechanisms yield a superconducting diode response would extend the reported phenomena beyond reciprocal Josephson transport.

References

On the other hand, since both space-inversion and time-reversal symmetries are simultaneously broken in altermagnetic CrSb, the emergence of a finite-momentum Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) state is, in principle, feasible. This could give rise to an unexplored superconducting diode effect.

— Strain-engineered long-distance supercurrent in an altermagnetic CrSb based-Josephson junction  (2610.11341 - Gao et al., 8 Oct 2026) in Discussion preceding the Conclusions section