Persistent Skyrmion Lattice of Noninteracting Electrons with Spin-Orbit Coupling

Abstract

A persistent spin helix (PSH) is a robust helical spin-density pattern arising in disordered 2D electron gases with Rashba $\alpha$ and Dresselhaus $\beta$ spin-orbit (SO) tuned couplings, i.e., $\alpha =\pm \beta$. 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 $\nu =1,2$. For realistic GaAs wells we show that the Rashba ${\alpha }_{\nu }$ and Dresselhaus ${\beta }_{\nu }$ couplings can be simultaneously tuned to equal strengths but opposite signs, e.g., ${\alpha }_1={\beta }_1$ and ${\alpha }_2=-{\beta }_2$. In this regime and away from band anticrossings, our {\it non-interacting} electron gas sustains a topologically non-trivial 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 non-interacting electrons.

5 pages, 2 figures; changed the presentation and added supplemental material (17 pages, 1 figure)

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Cited by in corpus (21)

• Persistent Spin Textures in Semiconductor Nanostructures
• Stretchable persistent spin helices in GaAs quantum wells
• Critical supercurrent and ${\varphi }_0$ state for probing a persistent spin helix
• Spin-orbit coupling in wurtzite quantum wells
• Spin-orbit coupling effects in zinc-blende InSb and wurtzite InAs nanowires: Realistic calculations with multiband $\vec{k}\cdot \vec{p}$ method
• Symmetry Breaking of the Persistent Spin Helix in Quantum Transport
• Spin drift and diffusion in one- and two-subband helical systems
• Gate control of the spin mobility through the modification of the spin-orbit interaction in two-dimensional systems
• Blurring the boundaries between topological and non-topological phenomena in dots
• Unique Spin Vortices in Quantum Dots with Spin-orbit Couplings
• Nonlinear emergent elasticity and structural transitions of skyrmion crystal under uniaxial distortion
• Chirality and intrinsic dissipation of spin modes in two-dimensional electron liquids
• Quantum oscillations in 2D electron gases with spin-orbit and Zeeman interactions
• Tuning the Topological Features of Quantum-Dot Hydrogen and Helium by a Magnetic Field
• Electrical control of spin relaxation anisotropy during drift transport in a two-dimensional electron gas
• Spin drift-diffusion for two-subband quantum wells
• Interband contributions to nonlinear transport in semiconductor nanostructures
• Charge-Spin Conversion in Two-Subband Quantum Wells with Conventional and Unconventional Rashba Spin-Orbit Coupling
• Monte Carlo Simulations of Spin Transport in a Strained Nanoscale InGaAs Field Effect Transistor
• Efficient method to calculate energy spectra for analysing magneto-oscillations
• An Unusual Dresselhaus Spin-Orbit Contribution of Even Order in Momentum