arXiv subjects

A. M. Somoza

Publications and source records attributed to A. M. Somoza.

22 records · Page 2Linked to original sources

arXiv2006

Conductance fluctuations in the localized regime

We have studied numerically the fluctuations of the conductance, $g$, in two-dimensional, three-dimensional and four-dimensional disordered non-interacting systems. We have checked that the variance of $\ln g$ varies with the lateral sample size as $L^{2/5}$ in three-dimensional systems, and as a logarithm in four-dimensional systems. The precise knowledge of the dependence of this variance with system size allows us to test the single-parameter scaling hypothesis in three-dimensional systems. We have also calculated the third cumulant of the distribution of $\ln g$ in two- and three-dimensional systems, and have found that in both cases it diverges with the exponent of the variance times 3/2, remaining relevant in the large size limit.

cond-mat.dis-nn↗

arXiv1999

Configuration space in electron glasses

We study numerically the configuration space at low energy of electron glasses. We consider systems with Coulomb interactions, short-range interactions and no interactions. First, we calculate the integrated density of configurations as a function of energy. At a given energy, this density is smaller for Coulomb glasses than for short-range systems, which in turn is smaller than for non-interacting systems. We analyze how the site occupancy varies with the number of configurations. Through this study we estimate the number of particles involved in a typical low-energy transition between configurations. This number increases with system size for long range interactions, while it is basically constant for a short-range interaction. Finally we calculate the density of metastable configurations, i.e. valleys, classified according to their degree of stability.

cond-mat.str-el↗

arXiv1998

Self-Assembled Triply Periodic Minimal Surfaces as moulds for Photonic Band Gap Materials

We propose systems with structures defined by self-assembled triply periodic minimal surfaces (STPMS) as candidates for photonic bandgap materials. To support our proposal we have calculated the photonic bands for different STPMS and we have found that, at least, the double diamond and gyroid structures present full photonic bandgaps. Given the great variety of systems which crystalize in these structures, the diversity of possible materials that form them and the range of lattice constants they present, the construction of photonic bandgap materials with gaps in the visible range may be presently within reach.

cond-mat.mtrl-sci↗

arXiv1996

Growth in systems of vesicles and membranes

We present a theoretical study for the intermediate stages of the growth of membranes and vesicles in supersaturated solutions of amphiphilic molecules. The problem presents important differences with the growth of droplets in the classical theory of Lifshitz-Slyozov-Wagner, because the aggregates are extensive only in two dimensions, but still grow in a three dimensional bath. The balance between curvature and edge energy favours the nucleation of small planar membranes, but as they grow beyond a critical size they close themselves to form vesicles. We obtain a system of coupled equations describing the growth of planar membranes and vesicles, which is solved numerically for different initial conditions. Finally, the range of parameters relevant in experimental situations is discussed.

cond-mat↗