Disorder-induced topological phase transitions in two-dimensional spin-orbit coupled superconductors

Abstract

Normal superconductors with Rashba spin-orbit coupling have been explored as candidate systems of topological superconductors. Here we present a comparative theoretical study of the effects of different types of disorder on the topological phases of two-dimensional Rashba spin-orbit coupled superconductors. First, we show that a topologically trivial superconductor can be driven into a chiral topological superconductor upon diluted doping of isolated magnetic disorder, which close and reopen the quasiparticle gap of the paired electrons in a nontrivial manner. Secondly, the superconducting nature of a topological superconductor is found to be robust against Anderson disorder, but the topological nature is not, converting the system into a topologically trivial state even in the weak scattering limit. These topological phase transitions are distinctly characterized by variations in the topological invariant. We discuss the central findings in connection with existing experiments, and provide new schemes towards eventual realization of topological superconductors.

Skyrmion-like textures in superconductors with competing orders

“…Nevertheless, both terms share the same physical origin, as they arise from inversion symmetry breaking. We study this model using Bogoliubov-deGennes (BdG) mean field simulations, an approach that has been extensively used to study the effect of SOC on superconductivity [35][36][37][38][39] . On an L × L lattice, we obtain a 4L 2 × 4L 2 matrix as the BdG Hamiltonian.…”

Disorder-induced topological phase transitions on Lieb lattices

“…The TAI has been investigated in many related models and systems, such as Haldane model, KaneMele model, the three dimensional Dirac-Wilson model and semimetal systems [32][33][34][35][36][37] . Topological phase transitions driven by disorder and transport properties have been studied in various electronic systems, in which many intriguing phenomena were observed due to the interplay between topology and disorder [38][39][40][41][42][43][44][45] .…”

Disorder-induced Majorana zero modes in a dimerized Kitaev superconductor chain

“…τ i and σ i are the Pauli matrices acting on the sublattice and the particle-hole degrees of freedom, respectively. In the Hamiltonian (5), the dimerization parameter η is coupled with the pairing strength ∆ and the hopping amplitude t. Since the selfenergy is independent of the momentum [66,67], the possible renormalization parameters are µ R = µ−Σ 0 , p +R = p + −Σ 1 and q +R = q + + Σ 2 .…”

“…Very recently, the experimental observation of the topological Anderson insulator has been reported in 1D disordered atomic chain based * binzhou@hubu.edu.cn on the SSH model [64] and optical lattices [65]. In addition, the disorder-induced topological phases in TSCs have also attracted much attention [66][67][68][69]. Analogous to the topological Anderson insulator, Borchmann et al proposed the concept of the Anderson topological superconductor, a disorder-induced topological state in superconductor systems [66].…”