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Register a new userAsymmetric Energy Transfer Between Coupled Magnetic Vortices by Asymmetric Gyration Amplification
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We present a numerical exploration of the possibility of sustained amplification of magnetic vortex gyration by controlling the relative polarities of a coupled vortices in short vortex chains. First, we numerically establish the asymmetry in gyration of a single vortex based on its polarity by use of external magnetic field rotating at the gyrotropic frequency. This phenomena can be used to design logical adapters if vortex core switching is avoided. The criteria to obtain a good gyration amplitude ratio to easily observe true or false output has been examined further. The cases of coupled magnetic vortices and short vortex chains have been studied with different polarity configurations to reveal other desirable aspects of vortex dynamics including, but not limited to, highly efficient signal transfer. These findings are important in applications for information signal processing.
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The influence of a strain-induced uniaxial magnetoelastic anisotropy on the magnetic vortex core dynamics in microstructured magnetostrictive Co$_{40}$Fe$_{40}$B$_{20}$ elements was investigated with time-resolved scanning transmission x-ray microscopy. The measurements revealed a monotonically decreasing eigenfrequency of the vortex core gyration with the increasing magnetoelastic anisotropy, which follows closely the predictions from micromagnetic modeling.
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We obtain a microscopic description of the interaction between electron spins in bulk semiconductors and in pairs of semiconductor quantum dots. Treating the k.p band mixing and the Coulomb interaction on the same footing, we obtain in the third order an asymmetric contribution to the exchange interaction arising from the coupling between the spin of one electron and the relative orbital motion of the other. This contribution does not depend on the inversion asymmetry of the crystal. We find that it is ~0.001 of the isotropic exchange, which is of interest in quantum information. Detailed evaluations are given for several quantum dot systems.
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In bilayers of two-dimensional (2D) semiconductors with stacking arrangements which lack inversion symmetry charge transfer between the layers due to layer-asymmetric interband hybridisation can generate a potential difference between the layers. We analyse bilayers of transition metal dichalcogenides (TMDs) - in particular, WSe$_2$ - for which we find a substantial stacking-dependent charge transfer, and InSe, for which the charge transfer is found to be negligibly small. The information obtained about TMDs is then used to map potentials generated by the interlayer charge transfer across the moire superlattice in twistronic bilayers.
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