The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Y Takahashi - One of the best experts on this subject based on the ideXlab platform.
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role of Commensurability of spin order for optical magnetoelectric effect with electromagnons in multiferroic ymn 2 o 5
Physical Review B, 2017Co-Authors: R Masuda, Yoshio Kaneko, Yuichi Yamasaki, Y Tokura, Y TakahashiAbstract:Multiferroic phases of materials like YM${}_{2}$O${}_{5}$ feature an optical magnetoelectric effect on the resonance of the electromagnon. The effect manifests itself in nonreciprocal directional dichroism. Here, the authors examine the role of the Commensurability of noncollinear spin order for the optical magnetoelectric effect for two types of electromagnon. For the electromagnon driven by the exchange striction, the crucial role of the Commensurability is indicated by the suppression of the directional dichroism by the magnetic phase transition. On the other hand, the gapped electromagnon due to the spin-current mechanism is identified by the directional dichroism, regardless of (in)Commensurability. These results provide new insights into the light-matter interaction driven by dynamical magnetoelectric coupling.
Rolf R Gerhardts - One of the best experts on this subject based on the ideXlab platform.
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Commensurability oscillations in a lateral superlattice with broken inversion symmetry
New Journal of Physics, 2015Co-Authors: M Staab, Dieter Weiss, M Matuschek, Pedro Pereyra, Martin Utz, Dieter Schuh, Dominique Bougeard, Rolf R GerhardtsAbstract:We investigate both, experimentally and theoretically, Commensurability oscillations in the low-field magnetoresistance of lateral superlattices with broken inversion symmetry. We find that pronounced minima develop in the resistivity when the flat band conditions of several relevant harmonics of the periodic potential nearly coincide.
E. Szuszkiewicz - One of the best experts on this subject based on the ideXlab platform.
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Occurrence of the 2:1 Commensurability in a gas giant-Super-Earth system
Monthly Notices of the Royal Astronomical Society, 2011Co-Authors: E. Podlewska-gaca, E. SzuszkiewiczAbstract:We investigate how the conditions occurring in a protoplanetary disc may determine the final structure of a planetary system emerging from such a disc. We concentrate our attention on the dynamical interactions between disc and planets leading to orbital migration, which in turn, in favourable circumstances, can drive planets into a mean-motion Commensurability. We find that for a system containing a gas giant on the external orbit and a Super-Earth on the internal one, both embedded in a gaseous disc, the 2:1 resonance is a very likely configuration, so one can expect it as an outcome of the early phases of the planetary system formation. Our conclusion is based on an extensive computational survey in which we ask what are the disc properties (the surface density and the viscosity) for which the 2:1 Commensurability may be attained. To answer this question we employ a full two-dimensional hydrodynamic treatment of the disc-planet interactions. In general terms, we can claim that the conditions which favour the 2:1 mean-motion resonance exist in the protoplanetary discs with mass accretion rates typical for slowly accreting T Tauri stars. For accretion rates higher than those needed for the 2:1 Commensurability we observe a variety of behaviours, among them the passage to the 3:2 resonance, the scattering of the Super-Earth or the divergent migration caused by the outward migration of the gas giant. The results we have obtained from numerical simulations are compared with the predictions coming from the existing analytical expressions of the migration speed and the strength of the mean motion resonances. The conditions that we have found for the attainment of the 2:1 Commensurability are discussed in the framework of the properties of protoplanetary discs that are known from the observations.Comment: 12 pages, 11 figures, accepted for publication in MNRA
A S De Wijn - One of the best experts on this subject based on the ideXlab platform.
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in Commensurability scaling and multiplicity of friction in nanocrystals and application to gold nanocrystals on graphite
Physical Review B, 2012Co-Authors: A S De WijnAbstract:The scaling of friction with the contact size A and (in)commensurabilty of nanoscopic and mesoscopic crystals on a regular substrate are investigated analytically for triangular nanocrystals on hexagonal substrates. The crystals are assumed to be stiff, but not completely rigid. Commensurate and incommensurate configurations are identified systematically. It is shown that three distinct friction branches coexist, an incommensurate one that does not scale with the contact size (A(0)) and two commensurate ones which scale differently (with A(1/2) and A) and are associated with various combinations of commensurate and incommensurate lattice parameters and orientations. This coexistence is a direct consequence of the two-dimensional nature of the contact layer, and such multiplicity exists in all geometries consisting of regular lattices. To demonstrate this, the procedure is repeated for rectangular geometry. The scaling of irregularly shaped crystals is also considered, and again three branches are found (A(1/4), A(3/4), A). Based on the scaling properties, a quantity is defined which can be used to classify Commensurability in infinite as well as finite contacts. Finally, the consequences for friction experiments on gold nanocrystals on graphite are discussed.
Roland Winkler - One of the best experts on this subject based on the ideXlab platform.
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Spin-resolved Commensurability oscillations
Physical Review B, 1999Co-Authors: Mansour Shayegan, L. Wissinger, Ulrich Rössler, Roland WinklerAbstract:We report the observation of Commensurability oscillations, induced by a one-dimensional periodic potential, in a high-mobility GaAs two-dimensional hole system confined to a triangular quantum well. The measured oscillations exhibit two frequencies that agree well with those calculated from the Fermi contours of the two spin-split hole subbands, providing clear evidence for the observation of spin-resolvedCommensurability oscillations.