The transmission of electromagnetic radiation at normal incidence through a finite antiferromagnetic-nonmagnetic superlattice is considered for an applied field normal to the interfaces (Faraday geometry) and for a field parallel to the interfaces (Voigt geometry). Besides the transmission spectra, we present the calculations of the dispersion curves for a relevant infinite superlattice to understand the features of the spectra. The transmission is weak or very weak at frequencies in the stop bands of the corresponding infinite superlattice, and these stop bands only appear at the Brillouin-zone edges (2n + 1)π/D, not at 2nπ/D.
Electronic transport through a double quantum dot interferometer with Rashba spin-orbit interaction is investigated. By means of the slave-boson mean-field approximation and Green function technique, we calculated the local density of states (DOS) and the linear conductance in the Kondo regime at zero temperature. It is shown that the local DOS and the linear conductance of each spin component can be tuned by the Rashba spin-orbit interaction with help of the magnetic flux. In particular, by modulating the strength of the Rashba spin-orbit interaction properly, only one spin component electron can be allowed to transport through this structure. 1 Introduction The Kondo effect in artificial quantum dots (QD) was predicted theoretically more than two decades ago [1,2]. The phenomenon in QD occurs because of a strong antiferromagnetic coupling between the localized spin in the QD and the conduction band electrons in the electrodes through higher-order tunneling processes. The resulting correlated motion gives rise to a Kondo singularity in the density of states (DOS) at the Fermi level and the enhanced conductance. The Kondo effect in the coupled QD has attracted much attention both experimentally and theoretically [3][4][5], recently. The flexibility in tuning various parameters of coupled quantum dos has enabled the study of Kondo phenomena in great detail.In addition, the Rashba spin-orbit (RSO) interaction is an important mechanism that influences the electron-spin state in low-dimensional structures [6][7][8]. The RSO interaction comes into play by introducing an electric field that destroys the symmetry of space inversion in an arbitrary spatial direction. In QD structures, the RSO interaction give rises to an extra spin-dependent phase factor in the coupling matrix elements between the leads and the QD and the inter-level spin-flip term [10]. Hence, the RSO interaction makes the quantum transport phenomena rich and complicated [9]. Recently, Vernek et al. [10] theoretically predicted that the combination of RSO interaction and the Aharonov-Bohm (AB) effect strongly suppresses the Kondo resonance, and Lim et al. [11] found
Based on the nonequilibrium Green function method, quantum transport through a benzene-shaped quantum dots system is studied. It is shown that the conductance spectrum is sensitive to the arrangement of energy levels of dots. When the energy levels of dots are mismatched, the conductance shows apparent asymmetric structure and striking novel conductance dips appear due to the interference between two distinct paths. The differential conductance as a function of magnetic flux always exhibits 2pi period. An overall suppression of differential conductance emerges for the condition that the levels of dots are all aligned and phi = (2n + 1)pi (n is an integer). In addition, the influence of temperature on the differential conductance is presented.
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