Decoherence of transported spin in multichannel spin-orbit coupled spintronic devices: Scattering approach to spin density matrix from the ballistic to the localized regime

Abstract

By viewing current in the detecting lead of a spintronic device as being an ensemble of flowing spins corresponding to a mixed quantum state, where each spin itself is generally described by an improper mixture generated during the transport where it couples to other degrees of freedom due to spin-orbit (SO) interactions or inhomogeneous magnetic fields, we introduce the spin density operator associated with such current expressed in terms of the spin-resolved Landauer transmission matrix of the device. This formalism, which provides complete description of coupled spin-charge quantum transport in open finite-size systems attached to external probes, is employed to understand how initially injected pure spin states, comprising fully spin-polarized current, evolve into the mixed ones corresponding to partially polarized current. We analyze particular routes that diminish spin coherence (signified by decay of the off-diagonal elements of the current spin density matrix) in two-dimensional electron gas-based devices due to the interplay of the Rashba and/or Dresselhaus SO coupling and: (i) scattering at the boundaries or lead-wire interface in ballistic semiconductor nanowires; or (ii) spin-independent scattering off static impurities in both weakly and strongly localized disordered nanowires. The physical interpretation of spin decoherence in the course of multichannel quantum transport in terms of the entanglement of spin to an effectively zero-temperature ``environment'' composed of more than one open orbital conducting channels offers insight into some of the key challenges for spintronics: controlling decoherence of transported spins and emergence of partially coherent spin states in all-electrical spin manipulation schemes based on the SO interactions in realistic semiconductor structures.

16 pages, 9 color figures

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Cited by in corpus (49)

• Can Non-Equilibrium Spin Hall Accumulation be Induced in Ballistic Nanostructures?
• Imaging mesoscopic spin Hall flow: Spatial distribution of local spin currents and spin densities in and out of multiterminal spin-orbit coupled semiconductor nanostructures
• Pseudospin-driven spin relaxation mechanism in graphene
• Mesoscopic Spin Hall Effect in Multiprobe Ballistic Spin-Orbit Coupled Semiconductor Bridges
• Spin-memory loss due to spin-orbit coupling at ferromagnet/heavy-metal interfaces: Ab initio spin-density matrix approach
• Wavevector-dependent spin filtering and spin transport through magnetic barriers in graphene
• Spin-transfer torque and spin-polarization in topological-insulator/ferromagnet vertical heterostructures
• Tunable pure spin currents in a triple-quantum-dot ring
• Transverse Spin-Orbit Force in the Spin Hall Effect in Ballistic Semiconductor Wires
• Microwave-driven ferromagnet--topological-insulator heterostructures: The prospect for giant spin battery effect and quantized charge pump devices
• Charge and spin dynamics driven by ultrashort extreme broadband pulses: a theory perspective
• Spin polarization in a T-shape conductor induced by strong Rashba spin-orbit coupling
• Anisotropic spin transport in two-terminal mesoscopic rings: the Rashba and Dresselhaus spin-orbit interactions
• Shot noise and spin-orbit coherent control of entangled and spin polarized electrons
• Effective Hamiltonian model for helically constrained quantum systems within adiabatic perturbation theory: application to the Chirality-Induced Spin Selectivity (CISS) Effect
• Semiclassical theory of weak antilocalization and spin relaxation in ballistic quantum dots
• Charge pumping by magnetization dynamics in magnetic and semi-magnetic tunnel junctions with interfacial Rashba or bulk extrinsic spin-orbit couplings
• Voltage controlled spin precession
• Effects of strain, electric, and magnetic fields on lateral electron spin transport in semiconductor epilayers
• Spin polarized current generation from quantum dots without magnetic fields
• Transit-Time Spin Field-Effect-Transistor
• A group-theoretic approach to the origin of chirality-induced spin selectivity in non-magnetic molecular junctions
• Spin-orbit interaction induced spin selective transmission through a multi-terminal mesoscopic ring
• Shot Noise of Spin-Decohering Transport in Spin-Orbit Coupled Nanostructures
• Curvature effect on spin polarization in a three-terminal geometry in presence of Rashba spin-orbit interaction
• Spin-polarized electric currents in quantum transport through tubular two-dimensional electron gases
• Quantum spin-transfer torque induced nonclassical magnetization dynamics and electron-magnetization entanglement
• Ballistic spin field-effect transistors: Multichannel effects
• Spin filtering implemented through Rashba and weak magnetic modulations
• Two-dimensional electron scattering in regions of nonuniform spin-orbit coupling
• What can we learn about the dynamics of transported spins by measuring shot noise in spin-orbit-coupled nanostructures?
• Spin-charge conversion in multiterminal Aharonov-Casher ring coupled to precessing ferromagnets: A charge conserving Floquet-nonequilibrium Green function approach
• Quantum-classical approach to spin and charge pumping and the ensuing radiation in THz spintronics: Example of ultrafast-light-driven Weyl antiferromagnet Mn${}_3$Sn
• Interplay between resonant tunneling and spin precession oscillations in all-electric all-semiconductor spin transistors
• Revisit the spin-FET: Multiple reflections, inelastic scattering, and lateral size effects
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• Rashba-Zeeman-effect-induced spin filtering energy windows in a quantum wire
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• Conductance oscillations of a spin-orbit stripe with polarized contacts
• Rashba-induced transverse pure spin currents in a four-terminal quantum dot ring
• Externally controlled selective spin transfer through a two-terminal bridge setup
• Spin-filtering and charge- and spin-switching effects in a quantum wire with periodically attached stubs
• Spin filtering in nanowire directional coupler
• Spin interference and Fano effect in electron transport through a mesoscopic ring side-coupled with a quantum dot
• Precessionless spin transport wire confined in quasi-two-dimensional electron systems
• Effects of scattering area shape on spin conductance in a four-terminal spin-Hall setup
• Spin polarization via decoherence in spin-orbit active media coupled to an electron reservoir
• Suppression of Spin Dephasing in a Two-Dimensional Electron Gas with a Quantum Point Contact