Related papers: Spin pumping and torque statistics in the quantum …
We theoretically propose quantum spin pumping mediated by magnons, under a time-dependent transverse magnetic field, at the interface between a ferromagnetic insulator and a non-magnetic metal. The generation of a spin current under a…
A time-dependent bias voltage on a tunnel junction generates a time-dependent modulation of its current fluctuations, and in particular of its variance. This translates into an excitation at frequency $\tilde{f}$ generating correlations…
In this study, current pumping by an external potential is studied on the basis of the Keldysh Green's function method, and a pumping formula written in terms of retarded and advanced Green's functions is obtained. It is shown that pumping…
This work brings together Keldysh non-equilibrium quantum theory and thermodynamics, by showing that a real-time diagrammatic technique is an equivalent of stochastic thermodynamics for non-Markovian quantum machines (heat engines,…
Pure spin current is a powerful tool for manipulating spintronic devices, and its dynamical behavior is an important issue. By using mesoscopic transport theory for electron tunneling induced by spin accumulation, we investigate the…
We derive an $n$-resolved Master equation for quantum transport that includes a dependence on the number $n$ of tunneled electrons in system parameters such as tunnel rates and energy levels. We apply the formalism to describe dynamical…
The thermal activation of magnetization reversal in magnetic nanoparticles is controlled by the anisotropy-energy barrier. Using perturbation theory, exact diagonalization and stability analysis of the ferromagnetic spin-s Heisenberg model…
A new physical mechanism for generating spin-transfer torque is proposed. It is due to interference of bias driven nonequilibrium electrons incident on a switching junction with the electrons reflected from an insulating barrier inserted in…
The edge channels of two-dimensional topological systems are protected from elastic reflection and are noiseless at low temperature. Yet, noise and cross-correlations can be induced when electron waves partly transmit to the opposite edge…
Microscopic theory of counting statistics of electrical noise is reviewed. We discuss a model of passive charge detector based on current fluctuations coupled to a spin, and its relation with the theory of photon counting in quantum optics.…
We study the dynamics of a quantum particle in a constricted two-dimensional channel and analyze how the onset of quantum corrections impacts the (semi-)classical high-temperature behaviour, as temperature is lowered. We characterize both…
In the thermodynamics of nanoscopic systems the relation between classical and quantum mechanical description is of particular importance. To scrutinize this correspondence we study an anharmonic oscillator driven by a periodic external…
Temperature plays an important role in spin torque switching of magnetic tunnel junctions causing magnetization fluctuations that decrease the switching voltage but also introduce switching errors. Here we present a systematic study of the…
Frequency dependent current noise in ferromagnetic double junctions with Coulomb blockade is studied theoretically in the limit of sequential tunneling. Two different relaxation processes are found in the correlations between spin polarized…
We study the incubation and transition times that characterize the magnetization switching induced by spin-orbit torques in nanomagnets with perpendicular anisotropy. We present a phenomenological model to interpret the dependence of the…
Coulomb blockade phenomena and quantum fluctuations are studied in mesoscopic metallic tunnel junctions with high charging energies. If the resistance of the barriers is large compared to the quantum resistance, transport can be described…
Understanding the magnetization dynamics induced by spin transfer torques in perpendicularly magnetized magnetic tunnel junction nanopillars and its dependence on material parameters is critical to optimizing device performance. Here we…
We theoretically investigate a thermoelectric heat engine based on a single-level quantum dot, calculating average quantities such as current, heat current, output power, and efficiency, as well as fluctuations (noise). Our theory is based…
A magnet with precessing magnetization pumps a spin current into adjacent leads. As a special case of this spin pumping, a precessing macrospin (magnetization) can assist electrons in tunneling. In small systems, however, the Coulomb…
We examine the quantum tunneling of magnetization in molecular spin in weak interaction with a bath subject to Redfield master equation. By designing a microscopic model for a multilevel spin system using only a generic Hamiltonian and…