Piezoelectric effect and diode effect in anapole and monopole superconductors

Abstract

Superconductors lacking both inversion symmetry and time-reversal symmetry have been attracting much attention as a platform for exotic superconducting phases and anomalous phenomena, including the superconducting diode effect. Recent studies revealed intrinsic phases with this symmetry, named anapole superconductivity and monopole superconductivity, which are P T -symmetric superconducting states with and without Cooper pairs' total momentum, respectively. To explore characteristic phenomena in these states, we calculate and predict the superconducting piezoelectric effect and superconducting diode effect. A close relationship with the finite-q pairing, asymmetric Bogoliubov spectrum, and quantum geometry is discussed. This study reveals the piezoelectric and diode effects as potential probes to elucidate exotic superconducting phases.

Photocurrent response in parity-time symmetric current-ordered states

“…called superconducting piezoelectric effect (Chazono et al, 2023(Chazono et al, , 2022. As in the case of the magnetizationsupercurrent correlation, the superconducting piezoelectric effect is clearly distinguished from the conventional (inverse) piezoelectric and magnetopiezoelectric effects in terms of the fields stimulating the strain, since the latter two effects are involved in the electric field and ohmic current, respectively.…”

Spin-Triplet Superconductivity from Quantum-Geometry-Induced Ferromagnetic Fluctuation

“…In the flatband systems [36,37,[47][48][49][50][51] the superfluid weight from Fermi-liquid theory vanishes, and the quantum geometric contribution determines the superfluid weight. The quantum geometry also plays essential roles in the monolayer FeSe [52] and some finite-momentum Cooper pairing states [53][54][55][56][57]. However, how quantum geometry affects the pairing mechanism of superconductivity has not been revealed.…”