We report measurements of the low temperature magnetic response of a line of 16 GaAs/GaAlAs connected mesoscopic rings whose total length is much larger than l φ . Using an on-chip micro-squid technology, we have measured a periodic response, with period h/e, corresponding to persistent currents in the rings of typical amplitude 0.40 ± 0.08 nA per ring. Direct comparison with measurements on the same rings but isolated is presented.PACS numbers: 73.20.Dx, 72.20.My In a mesoscopic metallic sample, quantum coherence of the electronic wave functions can affect drastically the equilibrium properties of the system. In the case of a metallic ring in a magnetic field, the new boundary conditions imposed by the magnetic flux [1] lead the wave functions and therefore all the thermodynamic properties of the system to be periodic with flux, with periodicity Φ 0 = h/e, the flux quantum. One of the most striking consequences of this, first pointed out by Büttiker, Imry and Landauer [2] for the 1D case, is that a mesoscopic normal-metal ring pierced by a magnetic flux carries a persistent non-dissipative current: this is a consequence of the periodicity of the free energy F (Φ) with flux, implying the existence of an equilibrium current I(Φ) = −∂F (Φ)/∂Φ. Subsequently, much theoretical effort has been devoted to the description of a realistic 3D disordered ring [3][4][5][6][7]. Both the sign and the amplitude of this current depend on the number of electrons in the ring and on the microscopic disorder configuration: thus this current, like other mesoscopic phenomena such as Aharonov-Bohm conductance oscillations [8], is sample specific. However, the order of magnitude of the current for a single, isolated ring can be characterized by its typical value I typ = I 2 , denoting the average over disorder configurations. It is given [6,7] by I typ = 1.56 I 0 l e /L. In this formula, I 0 = ev F /L where v F is the Fermi velocity and L the perimeter of the ring, and l e is the elastic mean free path: the current varies as the inverse of the diffusion time τ D = L 2 /D where D = v F l e is the diffusion constant. When measuring an ensemble of rings, the typical current per ring decreases as 1/ √ N R , where N R is the number of rings. At finite temperature [6,7,9], mixing of the energy levels reduces the current on the scale of the Thouless energy E c , the energy scale for energy correlations. Further reduction arises when temperature reduces the phase coherence length l φ down to values lower than L.For a long time, persistent currents were believed to be a specific property of isolated systems [2]. However, recent theoretical predictions suggest that persistent currents should exist even in connected rings. Using a semi-classical model in the diffusive limit, ref.[10] calculated persistent currents in various networks of connected rings, showing that the amplitude of the persistent currents should be reduced only weakly as compared to its value in the same network of isolated rings, whereas all the other properties, like temper...

We present measurements of the magnetoconductance of long and narrow quasi-one-dimensional gold wires containing magnetic iron impurities in a temperature range extending from 15 mK to 4.2 K. The dephasing rate extracted from the weak antilocalization shows a pronounced plateau in a temperature region of 300-800 mK, associated with the phase breaking due to the Kondo effect. Below the Kondo temperature, the dephasing rate decreases linearly with temperature, in contradiction with standard Fermi-liquid theory. Our data suggest that the formation of a spin glass due to the interactions between the magnetic moments is responsible for the observed anomalous temperature dependence.

Silicon photonics is one of the most prominent technology platforms for integrated photonics and can support a wide variety of applications. As we move towards a mature industrial core technology, we present the integration of silicon nitride (SiN) material to extend the capabilities of our silicon photonics platform. Depending on the application being targeted, we have developed several integration strategies for the incorporation of SiN. We present these processes, as well as key components for dedicated applications. In particular, we present the use of SiN for athermal multiplexing in optical transceivers for datacom applications, the nonlinear generation of frequency combs in SiN micro-resonators for ultra-high data rate transmission, spectroscopy or metrology applications and the use of SiN to realize optical phased arrays in the 800–1000 nm wavelength range for Light Detection And Ranging (LIDAR) applications. These functionalities are demonstrated using a 200 mm complementary metal-oxide-semiconductor (CMOS)-compatible pilot line, showing the versatility and scalability of the Si-SiN platform.

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