2014/01/31 by Younghyun Kim, Meng Cheng, Bela Bauer +2 · 2 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Condensed matter physics #Coupling (piping) #Electron #Fermi gas #Materials science #Phase (matter) #Phase diagram #Physics #Quantum and electron transport phenomena #Quantum mechanics #Spin (aerodynamics) #Spins #Superconductivity #Topological Materials and Phenomena #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.90.060401
published as Phys. Rev. B 90, 060401(R) (2014) · Final version, accepted to PRB(R)
arxiv created 2014/07/29 · openalex publication_date 2014/08/04 · arxiv updated 2014/08/05 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We theoretically obtain the phase diagram of localized magnetic impurity spins arranged in a one-dimensional chain on top of a one- or two-dimensional electron gas. The interactions between the spins are mediated by the Ruderman-Kittel-Kasuya-Yosida mechanism through the electron gas. Recent work predicts that such a system may intrinsically support topological superconductivity without spin-orbit coupling when a helical spin-density wave is spontaneously formed in the spins, and superconductivity is induced in the electron gas. We analyze, using both analytical and numerical techniques, the conditions under which such a helical spin state is stable in a realistic situation in the presence of disorder. We show that (i) it appears only when the spins are coupled to a (quasi-) one-dimensional electron gas, and (ii) it becomes unstable towards the formation of (anti)ferromagnetic domains if the disorder in the impurity spin positions \ensuremathδR becomes comparable with the Fermi wavelength. We also examine the stability of the helical state against Gaussian potential disorder in the electronic system using a diagrammatic approach. Our results suggest that in order to stabilize the helical spin state and thus the emergent topological superconductivity under realistic experimental conditions, a sufficiently strong Rashba spin-orbit coupling, giving rise to Dzyaloshinskii-Moriya interactions, is required.