Search results for "electron spin relaxation"
showing 6 items of 6 documents
Importance of Spin-Orbit Interaction for the Electron Spin Relaxation in Organic Semiconductors
2013
Despite the great interest organic spintronics has recently attracted, there is only a partial understanding of the fundamental physics behind electron spin relaxation in organic semiconductors. Mechanisms based on hyperfine interaction have been demonstrated, but the role of the spin-orbit interaction remains elusive. Here, we report muon spin spectroscopy and time-resolved photoluminescence measurements on two series of molecular semiconductors in which the strength of the spin-orbit interaction has been systematically modified with a targeted chemical substitution of different atoms at a particular molecular site. We find that the spin-orbit interaction is a significant source of electro…
Monte Carlo Simulation of Electron Dynamics in Doped Semiconductors Driven by Electric Fields: Harmonic Generation, Hot-Carrier Noise and Spin Relaxa…
2011
In solid state electronics the miniaturization of integrated circuits implies that, even at moderate applied voltages, the components can be exposed to very intense electric fields. Advances in electronics push the devices to operate also under cyclostationary conditions, i.e. under large-signal and time-periodic conditions. A main consequence of this fact is that circuits exhibit a strongly nonlinear behavior. Furthermore, semiconductor based devices are always imbedded into a noisy environment that could strongly affect their performance, setting the lower limit for signal detection in electronic circuits. For this reason, to fully understand the complex scenario of the nonlinear phenomen…
Phonon-induced spin relaxation of conduction electrons in silicon crystals
2014
Experimental works managing electrical injection of spin polarization in n-type and p-type silicon have been recently carried out up to room-temperature. In spite of these promising experimental results, a comprehensive theoretical framework concerning the influence of transport conditions on phonon-induced electron spin depolarization in silicon structures, in a wide range of values of lattice temperature, doping concentration and amplitude of external fields, is still at a developing stage. In order to investigate the spin transport of conduction electrons in lightly doped n-type Si crystals, a set of semiclassical multiparticle Monte Carlo simulations has been carried out. The mean spin …
Monte Carlo investigation of electron spin relaxation in GaAs crystals during low-field transport
2011
A great emerging interest within the condensed matter physics is the use of electron spin in semiconductor-based spintronic devices to perform both logic operations, communication and storage. In order to make spintronics a feasible technology, sufficiently long spin lifetimes and the possibility to manipulate, control and detect the spin polarization are required. The loss of spin polarization before, during and after the necessary operations is a crucial problem into spin device design; thus, a full understanding of the role played by the lattice temperature, the doping density and the amplitude of the applied electric field on the electron spin dynamics in semiconductors is essential for…
Metastability and Relaxation in Quantum and Mesoscopic Systems
2013
The transient dynamics and the relaxation of three quantum and mesoscopic systems are investigated. In particular we analyze: (i) a long Josephson junction (LJJ) driven by a non-Gaussian Lévy noise current; (ii) a metastable quantum dissipative system driven by an external periodical driving; and (iii) the electron spin relaxation process in n-type GaAs crystals driven by a fluctuating electric field. Specifically, in the first system the LJJ phase evolution is described by the perturbed sine-Gordon equation. We find the noise enhanced stability and resonant activation phenomena, by investigating the mean escape time as a function of the bias current frequency, noise intensity and length of…
Nonlinear relaxation in quantum and mesoscopic systems
2013
The nonlinear relaxation of three mesoscopic and quantum systems are investigated. Specifically we study the nonlinear relaxation in: (i) a long Josephson junction (LJJ) driven by a non-Gaussian Lévy noise current; (ii) a metastable quantum open system driven by an external periodical driving; and (iii) the electron spin relaxation process in n-type GaAs crystals driven by a fluctuating electric field. In the first system the LJJ phase evolution is described by the perturbed sine-Gordon equation. Two well known noise induced effects are found: the noise enhanced stability and resonant activation phenomena. We investigate the mean escape time as a function of the bias current frequency, nois…