arXiv subjects

Giuseppe Iannaccone

Publications and source records attributed to Giuseppe Iannaccone.

59 records · Page 4Linked to original sources

arXiv2004

Statistical model of dephasing in mesoscopic devices introduced in the scattering matrix formalism

We propose a phenomenological model of dephasing in mesoscopic transport, based on the introduction of random phase fluctuations in the computation of the scattering matrix of the system. A Monte Carlo averaging procedure allows us to extract electrical and microscopic device properties. We show that, in this picture, scattering matrix properties enforced by current conservation and time reversal invariance still hold. In order to assess the validity of the proposed approach, we present simulations of conductance and magnetoconductance of Aharonov-Bohm rings that reproduce the behavior observed in experiments, in particular as far as aspects related to decoherence are concerned.

cond-mat.mes-hall↗

arXiv2004

Two-dimensional hole precession in an all-semiconductor spin field effect transistor

We present a theoretical study of a spin field-effect transistor realized in a quantum well formed in a p--doped ferromagnetic-semiconductor- nonmagnetic-semiconductor-ferromagnetic-semiconductor hybrid structure. Based on an envelope-function approach for the hole bands in the various regions of the transistor, we derive the complete theory of coherent transport through the device, which includes both heavy- and light-hole subbands, proper modeling of the mode matching at interfaces, integration over injection angles, Rashba spin precession, interference effects due to multiple reflections, and gate-voltage dependences. Numerical results for the device current as a function of externally tunable parameters are in excellent agreement with approximate analytical formulae.

cond-mat.mes-hall↗

arXiv1995

General relation between state density and dwell times in mesoscopic systems

A relevant relation between the dwell time and the density of states for a three dimensional system of arbitrary shape with an arbitrary number of incoming channel is derived. This result extends the one obtained by Gasparian et al. for the special case of a layered one dimensional symmetrical system. We believe that such a strong relation between the most widely accepted time related to the dynamics of a particle and the density of states in the barrier region, one of the most relevant properties of a system in equilibrium, is rich of physical significance.

quant-ph↗

arXiv1995

A compact formula for the density of states in a quantum well

In this paper we derive a formula for the density of states in the presence of inelastic scattering in the quantum well of a double barrier structure as a function of a characteristic time of the motion of electrons (namely, the round trip time in the well) and of transmission probabilities for the whole structure and for each barrier. In the model we use the scattering processes due to phonons, impurities, and interface roughness, are taken into account by a unique fenomenological parameter, the mean free path, which plays the role of a relaxation length. We also show that, for lower rates of incoherent processes, the derived formula reduces to the one obtained by means of the Breit-Wigner formalism.

cond-mat↗

arXiv1995

A unified approach to electron transport in double barrier structures

In this paper we show an approach to electron transport in double barrier structures which unifies the well known sequential and resonant tunneling models in the widest range of transport regimes, from completely coherent to completely incoherent. In doing so, we make a clear distinction between ``approaches'' and ``transport regimes,'' in order to clarify some ambiguities in the concept of sequential tunneling. Scattering processes in the well are accounted for by means of an effective mean free path, which plays the role of a relaxation length. Our approach is based on a recently derived formula for the density of states in a quantum well, as a function of the round trip time in the well and of trasmission and reflection probabilities for the whole structure and for each barrier.

cond-mat↗