Initial pseudo-steady state & asymptotic KPZ universality in semiconductor on polymer deposition

The Kardar-Parisi-Zhang (KPZ) class is a paradigmatic example of universality in nonequilibrium phenomena, but clear experimental evidences of asymptotic 2D-KPZ statistics are still very rare, and far less understanding stems from its short-time behavior. We tackle such issues by analyzing surface fluctuations of CdTe films deposited on polymeric substrates, based on a huge spatio-temporal surface sampling acquired through atomic force microscopy. A \textit{pseudo}-steady state (where average surface roughness and spatial correlations stay constant in time) is observed at initial times, persisting up to deposition of $\sim 10^{4}$ monolayers. This state results from a fine balance between roughening and smoothening, as supported by a phenomenological growth model. KPZ statistics arises at long times, thoroughly verified by universal exponents, spatial covariance and several distributions. Recent theoretical generalizations of the Family-Vicsek scaling and the emergence of log-normal distributions during interface growth are experimentally confirmed. These results confirm that high vacuum vapor deposition of CdTe constitutes a genuine 2D-KPZ system, and expand our knowledge about possible substrate-induced short-time behaviors.Comment: 13 pages, 8 figures, 2 table

Universal zero-bias conductance through a quantum wire side-coupled to a quantum dot

A numerical renormalization-group study of the conductance through a quantum wire side-coupled to a quantum dot is reported. The temperature and the dot-energy dependence of the conductance are examined in the light of a recently derived linear mapping between the Kondo-regime temperature-dependent conductance and the universal function describing the conductance for the symmetric Anderson model of a quantum wire with an embedded quantum dot. Two conduction paths, one traversing the wire, the other a bypass through the quantum dot, are identified. A gate potential applied to the quantum wire is shown to control the flow through the bypass. When the potential favors transport through the wire, the conductance in the Kondo regime rises from nearly zero at low temperatures to nearly ballistic at high temperatures. When it favors the dot, the pattern is reversed: the conductance decays from nearly ballistic to nearly zero. When the fluxes through the two paths are comparable, the conductance is nearly temperature-independent in the Kondo regime, and a Fano antiresonance in the fixed-temperature plot of the conductance as a function of the dot energy signals interference. Throughout the Kondo regime and, at low temperatures, even in the mixed-valence regime, the numerical data are in excellent agreement with the universal mapping.Comment: 12 pages, with 9 figures. Submitted to PR

Influência do teor de alumínio do solo sobre a infestação de Heliothis zea (Boddie, 1850) em milho.

O objetivo deste trabalho foi avaliar o efeito do nivel de aluminio do solo sobre a infestacao de H. zea na cultura do milho. Atraves de calagem diferencial foram obtidas faixas de solo com 3 classes diferentes em relacao ao teor de aluminio (baixo = 0,15 meq/100 cm3); (medio = 0,8 meq/100 cm3; alto = 1,4 meq/100 cm3), cada classe constituindo um tratamento. A infestacao por H. zea foi natural. No primeiro ano, que foi mais seco, nao houve diferenca significativa entre as classes de solo. No ano seguinte, a porcentagem de espigas infestadas foi 43,59% no solo com baixo teor de aluminio e significativamente maior que no solo com alto teor de aluminio, onde a porcentagem de infestacao foi de 52%, 81%; o mesmo acontecendo com a profundidade de penetracao da lagarta na espiga) e 19,69 mm nos solos com baixo e alto teor de aluminio, respectivamente. No solo com teor de aluminio medio, os valores foram intermediarios para todos os parametros. As espigas produzidas no solo com baixo teor de aluminio (141,12 mm) foram maiores que no com baixo teor de aluminio (141,12 mm) foram maiores que no solo com alto teor de aluminio (112,80 mm). Esses resultados mostraram que ha influencia do aluminio do solo sobre H. zea