Spin backflow: a non-Markovian effect on spin pumping
arXiv:1901.04965 · doi:10.1103/PhysRevB.99.205304
Abstract
The miniaturization of spintronic devices, specifically, nanoscale devices employing spintronics, has attracted intensive attention from a scientific as well as engineering perspective. In this paper, we study non-Markovian effect on spin pumping to describe spin current generation driven by arbitrary precession frequency of magnetization in a quantum dot attached to an electron lead. Although the Markovian approximation can be used when driving is sufficiently slow compared with relaxation times in electron tunneling, recent developments in nano-spintronic devices show that we need to include non-Markovian effects. In contrast to the one-way-only nature of the spin current generation under the Markovian dynamics, we find that the non-Markovian dynamics exhibits a temporal backflow of spin, call spin backflow for brevity. We capture the phenomenon by introducing its quantifier, and show that the backflow significantly reduces the amount of spin current when the frequency exceeds the relaxation rate. This prevents unphysical divergence of the spin current in the high frequency limit that occurs under the Markovian approximation. We believe our analysis provides an understanding of the spin pumping particularly in regard to producing a more efficient spin current generation over shorter time scales by going beyond the conventional Markovian approximation.
References in corpus (33)
- Enhanced Gilbert Damping in Thin Ferromagnetic Films
- Measure for the Degree of Non-Markovian Behavior of Quantum Processes in Open Systems
- Nonequilibrium fluctuations, fluctuation theorems, and counting statistics in quantum systems
- Non-Markovian dynamics in open quantum systems
- Entanglement and non-Markovianity of quantum evolutions
- Quantum Non-Markovianity: Characterization, Quantification and Detection
- Spin pumping and magnetization dynamics in metallic multilayers
- Assessing non-Markovian dynamics
- Quantum Fisher Information Flow in Non-Markovian Processes of Open Systems
- On the degree of non-Markovianity of quantum evolution
- Geometrical characterization of non-Markovianity
- Foundations and Measures of Quantum Non-Markovianity
- An Adiabatic Quantum Pump of Spin Polarized Current
- Quantum spin field effect transistor
- AC-driven double quantum dots as spin pumps and spin filters
- Effective gauge field theory of spintronics
- Spin Polarized Transport Through a Single-Molecule Magnet: Current-Induced Magnetic Switching
- Energy backflow and non-Markovian dynamics
- Adiabatic charge and spin pumping through quantum dots with ferromagnetic leads
- Evidence for Suppression of Superconductivity by Spin Imbalance in Co-Al-Co single electron transistors
- Adiabatic response for Lindblad dynamics
- Crossover from Kondo assisted suppression to co-tunneling enhancement of tunneling magnetoresistance via ferromagnetic nanodots in MgO tunnel barriers
- Charge and spin pumping through a double quantum dot
- Inelastic scattering and heating in a molecular spin pump
- Non-adiabatic two-parameter charge and spin pumping in a quantum dot
- Non-adiabatic effect on the quantum heat flux control
- Interaction effect on adiabatic pump of charge and spin in quantum dot
- Consistent microscopic analysis of spin pumping effects
- Theory of spin pumping through an interacting quantum dot tunnel coupled to a ferromagnet with time-dependent magnetization
- Adiabatic pumping through an interacting quantum dot with spin-orbit coupling
- Spin pumping through quantum dots
- Green's function representation of spin pumping effect
- Nonadiabaticity in spin pumping under relaxation