Topological d-wave superconductivity in two dimensions

TL;DR

This paper reviews the potential for realizing topological d-wave superconductivity in two-dimensional noncentrosymmetric systems, highlighting how Zeeman fields and stacking structures can induce various topological phases, with implications for high-temperature superconductivity.

Contribution

It introduces a new approach to achieve topological superconductivity using noncentrosymmetric d-wave superconductors and Floquet engineering, expanding the possibilities beyond traditional methods.

Findings

Noncentrosymmetric d-wave superconductors become topological under infinitesimal Zeeman fields.

Stacking structures can induce parity transitions and diverse topological phases.

Proposes heterostructures of correlated electron systems as platforms for high-temperature topological superconductivity.

Abstract

Despite intensive searches for topological superconductors, the realization of topological superconductivity remains under debate. Previous proposals for the topological $s$-wave, $p$-wave, and chiral $d$-wave superconductivity have both advantages and disadvantages. In this review, we discuss two-dimensional topological superconductivity based on the non-chiral $d$-wave superconductors. It is shown that the noncentrosymmetric $d$-wave superconductors become topological superconductors under an infinitesimal Zeeman field without fine-tuning of parameters. Floquet engineering for introducing the Zeeman field in a controllable way is also proposed. When the two-dimensional noncentrosymmetric superconductors are stacked to recover the global inversion symmetry, the field-induced parity transition may occur, and the high-field odd-parity superconducting state realizes various topological phases depending on the stacking structures. Two-dimensional heterostructures of strongly correlated electron systems, which have been developed by recent experiments, are proposed as a platform of the high-temperature topological superconductivity and the interplay of topology and strong correlations in superconductors.