Odd-parity spin-loop-current order mediated by transverse spin fluctuations in cuprates and related electron systems

Unconventional symmetry-breaking phenomena due to nontrivial order parameters attract increasing attention in strongly correlated electron systems. Here, we predict theoretically the occurrence of nanoscale spontaneous spin-current, called spin loop-current (sLC) order, as a promising origin pseudogap and electronic nematicity cuprates. We reveal that sLC is driven by odd-parity electron-hole condensation are mediated transverse fluctuations around temperature $T^*$. At same temperature, magnon pair occurs. The "hidden" neither internal magnetic field nor charge density modulation induced, whereas predicted with finite wavenumber naturally gives Fermi arc structure. In addition, work attractive pairing interaction between adjacent hot spots, which enlarges d-wave superconducting transition $T_c$. state will be key ingredient understanding pseudogap, well superconductivity cuprates other metals.