2015/07/31 by Jiyong Fu, Poliana H. Penteado, Marco O. Hachiya +2 · 51 citations
Physics and Astronomy · #Condensed matter physics #Coupling (piping) #Delocalized electron #Electron #Excitation #Lattice (music) #Magnetic properties of thin films #Materials science #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum mechanics #Skyrmion #Spin (aerodynamics) #Superposition principle #Topological insulator #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevlett.117.226401
published in Physical Review Letters 117(22), 226401 (American Physical Society) · 5 pages, 2 figures; changed the presentation and added supplemental material (17 pages, 1 figure)
arxiv created 2016/11/23 · openalex publication_date 2016/11/23 · arxiv updated 2016/11/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
A persistent spin helix (PSH) is a robust helical spin-density pattern arising in disordered 2D electron gases with Rashba \ensuremathα and Dresselhaus \ensuremathβ spin-orbit (SO) tuned couplings, i.e., \ensuremathα=\ifmmode±\else\textpm\fi\ensuremathβ. Here, we investigate the emergence of a persistent Skyrmion lattice (PSL) resulting from the coherent superposition of PSHs along orthogonal directions---crossed PSHs---in wells with two occupied subbands \ensuremathν=1, 2. For realistic GaAs wells, we show that the Rashba \ensuremathα_\ensuremathν and Dresselhaus \ensuremathβ_\ensuremathν couplings can be simultaneously tuned to equal strengths but opposite signs, e.g., \ensuremathα1=\ensuremathβ1 and \ensuremathα2=\ensuremath-\ensuremathβ2. In this regime, and away from band anticrossings, our noninteracting electron gas sustains a topologically nontrivial Skyrmion-lattice spin-density excitation, which inherits the robustness against spin-independent disorder and interactions from its underlying crossed PSHs. We find that the spin relaxation rate due to the interband SO coupling is comparable to that of the cubic Dresselhaus term as a mechanism of the PSL decay. Near anticrossings, the interband-induced spin mixing leads to unusual spin textures along the energy contours beyond those of the Rahsba-Dresselhaus bands. Our PSL opens up the unique possibility of observing topological phenomena, e.g., topological and Skyrmion Hall effects, in ordinary GaAs wells with noninteracting electrons.