A recent experiment on the bulk compound 4Hb-TaS2 reveals an unusual time-reversal-symmetry-breaking superconducting state that possesses a magnetic memory not manifest in the normal state [1]. Here we provide a possible mechanism for this observation by studying the magnetic and electronic properties of 4Hb-TaS2. We discuss the criterion for a small magnetization in the normal state in terms of the spin and orbital magnetizations.
Based on an analysis of 4Hb-TaS2’s lattice symmetry and Fermi surface structure, we propose a simple mechanism that gives rise to the experimentally observed magnetic memory in 4Hb-TaS2: ferromagnetism mediated superconductivity in the interlayer, spin triplet channel, and the spin pairing imbalance leads to amplified magnetization in the superconducting state. We give a detailed analysis for the pairing symmetry and the orbital magnetization in the superconducting state. Finally, we discuss how our proposed pairing can be probed experimentally in terms of the spin polarized superconducting vortices.
[1] Kalisky et al., Nature 607, 692 (2022).
