Electron g factor in one- and zero-dimensional semiconductor nanostructures

We investigate theoretically the Zeeman effect on the lowest confined electron in quantum wires and quantum dots. A general relation is established between the symmetry of a low-dimensional system and properties of the electron g factor tensor, g _{\alpha$$\beta} . The powerful method used earlier to calculate the transverse g factor in quantum wells is extended to one-dimensional (1D) and 0D zinc-blende-based nanostructures and analytical expressions are derived in the frame of Kane's model for the g factors in quantum wells, cylindrical wires, and spherical dots. The role of dimensionality is illustrated on two particular heteropairs, GaAs/Al$_{x}$Ga$_{1-x}$As and Ga$_{1-x}$In$_{x}$As/InP. The efficiency of the developed theoretical concept is demonstrated by calculating the three principal values of the g factor tensor in rectangular quantum wires in dependence on the wire width to establish also the connection with the 2D case

Deep structure of crust and mantle beneath Iberia and Western Mediterranean from P and S Receiver functions and SKS Waveforms

We have conducted a P and S receiver functions [PRFs and SRFs] analysis for 19 seismic stations on the Iberia and western Mediterranean. In the transition zone [TZ] the PRFs analysis reveals a band [from Gibraltar to Balearic] increased by 10-20 km relative to the standard 250 km. The TZ thickness variations are strongly correlated with the P660s times in PRFs. We interpret the variable depth of the 660-km discontinuity as an effect of subduction. Over the anomalous TZ we found a reduced velocity zone in the upper mantle. Joint inversion of PRFs and SRFs reveals a subcrustal high S velocity lid and an underlying LVZ. A reduction of the S velocity in the LVZ is less than 10%. The Gutenberg discontinuity is located at 65±5 km, but in several models sampling the Mediterranean, the lid is missing or its thickness is reduced to ~30 km. In the Gibraltar and North Africa this boundary is located at ~100 km. The lid Vp/Vs beneath Betics is reduced relative to the standard 1.8. Another evidence of the Vp/Vs anomaly is provided by S410p phase late arrivals in the SRFs. The azimuthal anisotropy analysis with a new technology was conducted at 5 stations and at 2 groups of stations. The fast direction in the uppermost mantle layer is ~90º in Iberian Massif. In Balearic is in the azimuth of ~120º. At a depth of ~60 km the direction becomes 90º. Anisotropy in the upper layer can be interpreted as frozen, whereas anisotropy in the lower layer is active, corresponding to the present-day or recent flow. The effect of the asthenosphere in the SKS splitting is much larger than the effect of the subcrustal lithosphere

Polarization-and phase sensitive microscopy of SHG nanocrystals.

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