Superconductivity and Local Inversion-Symmetry Breaking

• DOI: 10.1146/annurev-conmatphys-040521-042511
• Publication Date: 2022-11-08T23:14:55Z
• Authors: Mark H. Fischer; Manfred Sigrist; Daniel F. Agterberg; Youichi Yanase
• Keywords: 3104 Condensed Matter Physics; Strongly Correlated Electrons (cond-mat.str-el); Topological superconductivity; 530 Physics; Condensed Matter - Superconductivity; FOS: Physical sciences; Rashba spin-orbit coupling; 10192 Physics Institute; Hidden spin polarization; 01 natural sciences; 2500 General Materials Science; Superconductivity (cond-mat.supr-con); Condensed Matter - Strongly Correlated Electrons; 0103 physical sciences; Topological superconductivity; Unconventional superconductivity; Rashba spin-orbit coupling; Hidden spin polarization; Unconventional superconductivity

Inversion and time reversal are essential symmetries for the structure of Cooper pairs in superconductors. The loss of one or both leads to modifications to this structure and can change the properties of the superconducting phases in profound ways. Superconductivity in materials lacking inversion symmetry, or noncentrosymmetric materials, has become an important topic. These materials show unusual magnetic and magnetoelectric properties and can host topological superconductivity. Recently, crystal structures with local, but not global, inversion-symmetry breaking have attracted attention. Here, superconductivity can exhibit phenomena not naively expected in centrosymmetric materials. In this review, we first introduce the concept of locally noncentrosymmetric crystals and different material realizations. We then discuss consequences of such local symmetry breaking on the normal state electronic structure and the classification of superconducting order parameters. Finally, we review the expected and, in parts, already observed phenomenology of unconventional superconductivity and possible topological superconducting phases.