Perfect Spin Filter by Periodic Drive of a Ferromagnetic Quantum Barrier

Abstract

We consider the problem of particle tunneling through a periodically driven ferromagnetic quantum barrier connected to two leads. The barrier is modeled by an impurity site representing a ferromagnetic layer or a quantum dot in a tight-binding Hamiltonian with a local magnetic field and an ac-driven potential, which is solved using the Floquet formalism. The repulsive interactions in the quantum barrier are also taken into account. Our results show that the time-periodic potential causes sharp resonances of perfect transmission and reflection, which can be tuned by the frequency, the driving strength, and the magnetic field. We demonstrate that a device based on this configuration could act as a highly tunable spin valve for spintronic applications.

Berry‐Phase in a Periodically Driven Single Molecule Magnet Transistor

“…More recently, the problem of electron transport through a periodically driven ferromagnetic quantum barrier with a local magnetic field and ac-driven potential was solved using the Floquet formalism. [16] In this letter, we present a theoretical study of the Berry-phase effect in electron transport through a SMM transistor under a local time periodic gate voltage and a transverse magnetic field, and show that the time periodic potential causes zero transmission resonances that oscillate as a function of the transverse magnetic field due to the Berry phase interference associated with two quantum tunneling paths. We show that the Berry phase oscillations can be detected in the conductance of the SMM transistor.…”

“…On the theoretical side, the electron transport properties in a SMM transistor were mostly investigated within a constant gate voltage. More recently, the problem of electron transport through a periodically driven ferromagnetic quantum barrier with a local magnetic field and ac‐driven potential was solved using the Floquet formalism …”

Engineering momentum profiles of cold-atom beams

“…Figure 1 summarizes our proposal. Analogous to a quantum switch device ('transistor') [7][8][9], the flux of particles from the 'source' (reservoir) is determined by the 'gate' (link potential). However, rather than simply controlling the overall transmission rate, our proposal allows one to design the momentum profile of the outgoing flux.…”

Thermoelectric Efficiency of a Topological Nano-Junction

“…At non-zero bias, the SC Green’s function depends on time due to the Josephson phase of the order parameter Equation ( 6 ), via the transformation with . Moreover, the time-dependence of the Josephson phase of the normal SC lead in Equation ( 6 ), determines a periodic time-dependence on the Green’s functions, and hence a Floquet representation [ 33 ] in Fourier space is the natural choice. Moreover, when Fourier transforming to the energy domain it is clear that, as a consequence of the voltage dependence of the Josephson phase, the Green’s functions acquire an energy shift , which we express as…”