Perfect spin polarization in T-shaped double quantum dots due to the spin-dependent Fano effect

Abstract

We study the spin-resolved transport properties of T-shaped double quantum dots coupled to ferromagnetic leads. Using the numerical renormalization group method, we calculate the linear conductance and the spin polarization of the current for various model parameters and at different temperatures. We show that an effective exchange field due to the presence of ferromagnets results in different conditions for Fano destructive interference in each spin channel. This spin dependence of the Fano effect leads to perfect spin polarization, the sign of which can be changed by tuning the dots' levels. Large spin polarization occurs due to Coulomb correlations in the dot, which is not directly coupled to the leads, while finite correlations in the directly-coupled dot can further enhance this effect. Moreover, we complement accurate numerical results with a simple qualitative explanation based on analytical expressions for the zero-temperature conductance. The proposed device provides a prospective example of an electrically-controlled, fully spin-polarized current source, which operates without an external magnetic field.

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Cited by in corpus (9)

• Spin-resolved thermal signatures of Majorana-Kondo interplay in double quantum dots
• Majorana-Kondo interplay in T-shaped double quantum dots
• The SU(4) Kondo effect in double quantum dots with ferromagnetic leads
• Anomalous Fano Resonance in Double Quantum Dot System Coupled to Superconductor
• Strong spin Seebeck effect in Kondo T-shaped double quantum dots
• Interplay of the Kondo effect with the induced pairing in electronic and caloric properties of T-shaped double quantum dots
• Magnetic Kondo regimes in a frustrated half-filled trimer
• Transport properties of proximitized double quantum dots
• Impact of electron-phonon coupling on electron transport through T-shaped arrangements of quantum dots in the Kondo regime