2021/03/30 by Patrycja Tulewicz, Kacper Wrześniewski, Kacper Wrzesniewski +2 · 14 citations
Physics and Astronomy · #Coupling (piping) #Ferromagnetism #Magnetic field #Magnetic properties of thin films #Magnetoresistance #Perturbation (astronomy) #Quantum #Quantum and electron transport phenomena #Quantum dot #Semiconductor Quantum Structures and Devices #Spin (aerodynamics) #Spin valve #cond-mat.mes-hall
paper · pdf · open access · doi:10.1103/physrevapplied.16.014029
published in Physical Review Applied 16(1) (American Physical Society) · 12 pages, 8 figures
arxiv created 2021/03/30 · openalex created_date 2021/04/13 · openalex publication_date 2021/07/12 · arxiv updated 2021/07/21 · openalex updated_date 2026/08/05
We study the spin-dependent transport properties of a spin valve based on a double quantum dot. Each quantum dot is assumed to be strongly coupled to its own ferromagnetic lead, while the coupling between the dots is relatively weak. The current flowing through the system is determined within perturbation theory in the hopping between the dots, whereas the spectrum of a quantum-dot--ferromagnetic-lead subsystem is determined by means of the numerical renormalization group method. The spin-dependent charge fluctuations between ferromagnets and quantum dots generate an effective exchange field, which splits the double-dot levels. Such a field can be controlled, separately for each quantum dot, by the gate voltages or by changing the magnetic configuration of the external leads. We demonstrate that the considered double-quantum-dot spin-valve setup exhibits enhanced magnetoresistive properties, including both normal and inverse tunnel magnetoresistance. We also show that this system allows for the generation of highly spin-polarized currents, which can be controlled by purely electrical means. The considered double quantum dot with ferromagnetic contacts can thus serve as an efficient voltage-tunable spin valve characterized by high output parameters.