Anderson topological superconductor

Abstract

In this paper we study the phase diagram of a disordered, spin-orbit coupled superconductor with s-wave or d + id-wave pairing symmetry in symmetry class D. We analyze the topological phase transitions by applying three different methods which include a disorder averaged entanglement entropy, a disorder averaged real-space Chern number, and an evaluation of the momentum space Chern number in a disorder averaged effective model. We find evidence for a disorder-induced topological state. While in the clean limit there is a single phase transition from a trivial phase with a Chern number C = 4 to a topological phase with C = 1, in the disordered system there is an intermediate phase with C = 3. The phase transition from the trivial C = 4 phase into the intermediate phase with C = 3 is seen in the real-space calculation of the Chern number. In spite of this, this phase transition is not detectable in the entanglement entropy. A second phase transition from the disorder induced C = 3 into the C = 1 phase is seen in all three quantities.

Interplay between topology and disorder in a two-dimensional semi-Dirac material

“…Specifically, it has been shown that the derivative of disorder-averaged entanglement entropy 22,[29][30][31][32][33] with respect to the parameters shows peaks near the transition as a consequence of gap closing. We therefore verify topological transitions discussed in the preceding section by calculating S, which is defined as S = −T r(ρ B ln ρ B ), where ρ B is the reduced density matrix of half of the sub-system B of original system.…”

“…While the role of disorder in three-dimensional Weyl metals and 2D quantum spin Hall insulators (QSH) [16][17][18][19][20][21][22] are well studied, the role of disorder in 2D semi-Dirac systems has received little attention 23,24 . Specifically, the interplay between topological states and disorder in SD systems is yet to be explored.…”

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

“…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].…”

“…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]. Recently, Lieu et al studied disorder effects on Kitaev chain model with longer-range hopping and pairing terms, and presented the transformation of phase boundaries under the influence of disorder [68].…”

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

“…More recently, in 1D topological superconducting systems, a nontopological localized phase has been obtained when the strength of the introduced Anderson disorder is in the strong scattering regime171819. In addition to these less desirable cases where the presence of disorder destroys the salient physical properties of the systems, there have also been numerous examples showing that properly introduced disorder can promote the emergence of intriguing phenomena in otherwise clean but ordinary host systems2021222324. One such example is the recent discovery of the topological Anderson insulating (TAI) state in HgTe quantum wells21.…”