Quantum Materials - 13

Abstract

Unlike conventional superconductors described by the BCS theory, the high-Tc superconductivity of cuprates and iron pnictides is believed to be driven by strong electron correlation effects. In particular, electronic nematic fluctuations have drawn significant interest and their role in the superconductivity offers an interesting subject [1]. The nematic instability leads to a state, which breaks only the rotational symmetry but preserves the translational symmetry. Recent studies [2-4] have identified the superconductivity near a nematic quantum critical point. However, they reached different conclusions about the pairing symmetry: Ref.[2] reported the d-wave symmetry whereas Refs.[3] and [4] the s-wave symmetry. To resolve this contradiction, we employ the Eliashberg theory, which accounts for the electron self-energy effect and the retardation effect. These effects were not considered in the previous studies [2-4] and can play an important role to the pairing symmetry, which we wish to discuss in our poster. In addition, the superconductivity can occur also inside the nematic phase, more generally in the presence of spatial anisotropy [5]. We wish to discuss the pairing symmetry even in this case.