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Abstract We report on a novel effect of temperature-dependent modulation in graphene-supported metamaterials. The effect was observed during the theoretical analysis of a model graphene-supported electro-optical modulator having silicon dioxide (SiO₂) or hafnium dioxide (HfO₂) as a buffer dielectric layer. Comparative analysis of the two materials showed that they provide approximately the same maximum values for transmission and reflection modulation depths. However, in the case of a HfO₂buffer layer, a lower chemical potential of the graphene is required to achieve the maximum value. Moreover, theoretical calculations revealed that a lower gate voltage (up to 6.4 times) is required to be applied in the case of a HfO₂layer to achieve the same graphene chemical potential. The graphene layer was found to possesses high absorption (due to the additional resonance excitation) for some values of chemical potential and this effect is extremely temperature dependent. The discovered modulation effect was demonstrated to further increase the transmission modulation depth for the simple model structure up to 2.7 times (from 18.4% to 50.1%), while for the reflection modulation depth, this enhancement was equal to 2.2 times (from 24.4% to 52.8%). The novel modulation effect could easily be adopted and applied over a wide range of metadevices which would serve as a quick booster for the development of related research areas. 

We simulate the motion of a commensurate vortex lattice in a periodic lattice of artificial circular pinning sites having different diameters, pinning strengths, and spacings using the time-dependent Ginzburg-Landau formalism. Above some critical DC current density Jc, the vortices depin, and the resulting steady-state motion then induces an oscillatory electric field E (t) with a defect "hopping" frequency f0, which depends on the applied current density and the pinning landscape characteristics. The frequency generated can be locked to an applied AC current density over some range of frequencies, which depends on the amplitude of the DC as well as the AC current densities. Both synchronous and asynchronous collective hopping behaviors are studied as a function of the supercell size of the simulated system and the (asymptotic) synchronization threshold current densities determined. 

We report on flux-flow properties of 50 nmthick thinfilm amorphous MoGe bridges of different sizes with and without patterned sub-micron holes with different diameters and spacings. Characterization of the devices was carried out in liquid He at 4.2 K in a magnetic field, H, applied perpendicular to the device plane. Two critical currents, Ic1 and Ic2, were studied. The current Ic1 is identified as the onset of a low-resistance state, whereas Ic2 is the current at which the device switches to a high-resistance state, and the corresponding dependences Ic1(H) and Ic2(H) were determined. In the absence of the holes, Ic1 decreases monotonically with H, whereas Ic2(H) manifests lobes resembling those in the Fraunhofer-like pattern characteristic of Josephson junctions. This behavior may be due to formation of an ordered vortex lattice in some current and field ranges. Introducing the hole-line arrays modifies both Ic1(H) and Ic2(H) in a way that is most complicated for larger hole diameters.