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In contrast to the predictions of the standard theory of electroconvection (EC), our experiments showed that the action of superposed ac and dc voltages rather inhibits pattern formation than favours the emergence of instabilities; the…

Soft Condensed Matter · Physics 2014-09-04 Peter Salamon , Nandor Eber , Balazs Fekete , Agnes Buka

The effect of superimposed ac and dc electric fields on the formation of electroconvection and flexoelectric patterns in nematic liquid crystals was studied. For selected ac frequencies an extended standard model of the electro-hydrodynamic…

Soft Condensed Matter · Physics 2015-06-19 Alexei Krekhov , Werner Decker , Werner Pesch , Nandor Eber , Peter Salamon , Balazs Fekete , Agnes Buka

Pattern forming instabilities induced by ultralow frequency sinusoidal voltages were studied in a rod-like nematic liquid crystal by microscopic observations and simultaneous electric current measurements. Two pattern morphologies,…

Soft Condensed Matter · Physics 2014-09-04 Peter Salamon , Nandor Eber , Alexei Krekhov , Agnes Buka

We report on the growth of domains of standing waves in electroconvection in a nematic liquid crystal. An ac voltage is applied to the system, forming an initial state that consists of travelling striped patterns with two different…

Soft Condensed Matter · Physics 2009-11-10 Carina Kamaga , Denis Funfschilling , Michael Dennin

Dielectric spectroscopy of a twist bend nematic phase of an achiral bent core liquid crystalline compound under DC bias is used to investigate its response to electric field. Two collective relaxation processes are revealed, these are…

Soft Condensed Matter · Physics 2018-09-12 K. Merkel , A. Kocot , J. K. Vij , G. Shanker

We report a liquid-crystal pattern-formation experiment in which we break the lateral (translational) symmetry of a nematic medium with a laser-induced thermal gradient. The work is motivated by an improved measurement (reported here) of…

Soft Condensed Matter · Physics 2009-11-11 Daniel R. Spiegel , Elliot R. Johnson , Skyler R. Saucedo

We report on the early time ordering in a nematic liquid crystal subjected to a sudden change in external ac electric field. We compare time evolution for two different initial states of electroconvection. Electroconvection is a highly…

Soft Condensed Matter · Physics 2007-05-23 Denis Funfschilling , Michael Dennin

We report experimental and theoretical results on the flexoelectric instability and crossover between flexoelectric domains and electroconvection in a hybrid aligned nematic MBBA under d.c. voltage. At threshold a spatially periodic…

Pattern Formation and Solitons · Physics 2007-05-23 V. A. Delev , A. P. Krekhov , L. Kramer

Homeotropic Nematic Liquid Crystal heated from above present convective Rayleigh-Benard instability for applied thermal gradients greater than $\Delta$Tc. This threshold increase with the intensity of applied external magnetic field…

Fluid Dynamics · Physics 2013-11-19 I. Bove , J. Salán

We discuss spatio-temporal pattern formation in two separate thermal convective systems. In the first system, hydrothermal waves (HTW) are modeled numerically in an annular channel. A temperature difference is imposed across the channel,…

Fluid Dynamics · Physics 2022-04-20 Atanu Chatterjee , Takahiko Ban , Atsushi Onizuka , Germano Iannacchione

The occurrence of phase fluctuations due to thermal excitations in Bose-Einstein condensates (BECs) is studied for a variety of temperatures and trap geometries. We observe the statistical nature of the appearence of phase fluctuations and…

Novel behavior in electroconvection (EC) has been detected in nematic liquid crystals (NLCs) under the condition of comparable timescales of the director relaxation and the period of the driving ac voltage. The studied NLCs exhibit standard…

Soft Condensed Matter · Physics 2009-11-13 Tibor Toth-Katona , Nandor Eber , Agnes Buka , Alexei Krekhov

For the first time the electrohydrodynamic convection (EHC) of nematic liquid crystals is studied via fully nonlinear simulation. As a system of rich pattern-formation the EHC is mostly studied with negative nematic liquid crystals…

Soft Condensed Matter · Physics 2016-12-28 Kuang-Wu Lee , Thorsten Pöschel

We present a neutron scattering study of stripe correlations measured on a single crystal of La$_{1.875}$Ba$_{0.125}$CuO$_{4}$. Within the low-temperature-tetragonal (LTT) phase, superlattice peaks indicative of spin and charge stripe order…

Strongly Correlated Electrons · Physics 2009-11-10 M. Fujita , H. Goka , K. Yamada , J. M. Tranquada , L. P. Regnault

Nematic drops suspended in the isotropic phase of the same substance were subjected to alternating electrical fields of varying frequency. The system was carefully kept in the isotropic-nematic coexistance region, which was broadened due to…

Soft Condensed Matter · Physics 2009-03-27 Günter K. Auernhammer , Jinyu Zhao , Beate Ullrich , Doris Vollmer

Suspended microparticles subjected to AC electrical fields collectively organize into band patterns perpendicular to the field direction. The bands further develop into zigzag shaped patterns, in which the particles are observed to…

Soft Condensed Matter · Physics 2022-02-16 Florian Katzmeier , Bernhard Altaner , Jonathan List , Ulrich Gerland , Friedrich C. Simmel

This study investigates the molecular-level mechanism of Alternating Current Electrohydrodynamic (AC-EHD) flow in nanopores under high-frequency conditions, using molecular dynamics simulations. A gold-NaCl system with symmetric and…

Soft Condensed Matter · Physics 2026-03-24 Sobin Alosious , Fiach Antaw , Matt Trau , Shern R. Tee , Debra J. Searles

Using the methods of computer modeling this scientific paper studies the special features of diffusion of the particles subjected to the external periodic force in the crystal lattice. The particle motion is described by a Langevin…

Statistical Mechanics · Physics 2011-11-04 I. G. Marchenko , I. I. Marchenko

The temporal evolution of the spatially periodic electroconvection (EC) patterns has been studied within the period of the driving ac voltage by monitoring the light intensity diffracted from the pattern. Measurements have been carried out…

Soft Condensed Matter · Physics 2015-05-27 Tibor Toth-Katona , Nandor Eber , Agnes Buka

The control of Mott phase is intertwined with the spatial reorganization of the electronic states. Out-of-equilibrium driving forces typically lead to electronic patterns that are absent at equilibrium, whose nature is however often…

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