Controllable spin diode based on a semiconductor quantum dot

Abstract

We theoretically propose an all-electrically controlled spin-current diode consisting of a quantum dot sandwiched between one normal electrode and one ferromagnetic electrode. By applying a spin bias VS across one electrode, the spin current distribution shows a rectification effect; that is, in the forward spin bias regime, a spin current can tunnel through the junction, while in the reverse bias regime, the current is tiny. Such asymmetry in the spin-current profile suggests diode-like behavior with respect to the spin bias. Moreover, the polarity direction of this spin-current diode can be manipulated and reversed by adjusting the gate voltage, which is much more feasible than the approach with traditional charge-current diodes. The present device can be realized by current technologies and has potential applications in spintronics or quantum information processing.

Spin-polarization and Coulomb interaction dependent thermal rectification in a quantum dot system

“…For a single QD system with two terminals, when the dot-lead coupling is asymmetrical, the single QD system with non-degenerate energy levels can exhibit a thermal rectification effect [24,28]. Previously, numerous investigations have examined the rectification of charge current in systems based on QDs, revealing diode-like behaviors in transport characteristics for QDs coupled to two ferromagnetic (FM) leads or to a nonmagnetic lead and a FM lead [35][36][37][38][39][40][41]. However, there is currently less research on the influence of the magnetic properties of the leads on the thermal rectification effect in such systems.…”

Electrical and Thermal Bias‐Driven Negative Magnetoresistance Effect in an Interacting Quantum Dot

“…[13][14][15] As another example, some asymmetric I-V current spectra are often found in structures in which QDs are coupled to ferromagnetic electrodes. [16][17][18][19][20][21] This special current distribution is gate voltage-controllable and very suitable for developing spin-based diode devices. Recently, much work has combined QD system research with thermoelectric effects.…”

Spin diode and spin valve based on an interacting quantum dot coupled with nonmagnetic electrodes

“…25,26) Moreover, recent studies have even utilized QDs to design diodes that can control spin rather than charge. [27][28][29] In their schemes, almost no charge current can be transported in the device, but the spin current flowing through it exhibits a rectification effect, which is named the "spin-current diode". [30][31][32] We know that diode devices are the most important electronic components of modern integrated circuits.…”

“…A small spin difference Δμ exists between the spin-up and spin-down chemical potentials in the source (S) lead, and a tunable electric bias voltage V e is applied across the junction. Although there have been some studies on the electron transport process in similar structures, [27][28][29][36][37][38][39][40] their main focus was on spin bias rather than electric bias. Our calculation results indicate that (i) without applying an external magnetic field, the current spectrum driven by the electric voltage (V e ) of this device exhibits a significant asymmetric distribution.…”