Momentum space imaging of locally noncentrosymmetric superconductors

TL;DR

This paper investigates how local noncentrosymmetry and quasi-spin-orbit coupling influence the electronic structure of certain superconductors, using momentum space imaging and quasiparticle interference techniques.

Contribution

It introduces the concept of symmetric and antisymmetric quasi-spin-orbit couplings in locally noncentrosymmetric crystals and analyzes their effects on electronic band structures.

Findings

Quasi-spin-orbit couplings significantly modify electronic band structures.

Distinct features arise from inter- and intra-sublattice hopping integrals.

Methodology applicable to transition metal oxides.

Abstract

The failure of spatial inversion symmetry in noncentrosymmetric materials introduces two different types of spin-independent and spin-dependent electron hopping. The spin-dependent term can be translated into a quasi-spin-orbit coupling and may affect the electronic structure. In the locally noncentrosymmetric crystals, the presence of a sublattice degree of freedom generates a distinction between the inter- and intra-sublattice hopping integrals. The spin-dependent part of the former (latter), which is even (odd) under parity, is called symmetric (antisymmetric) quasi-spin-orbit coupling. Here, we show the consequences of such quasi-spin-orbit couplings on the electronic band structure and study their characteristic features via the quasiparticle interference method. We extend our discussions to a realistic class of materials, known as transition metal oxides.