| Description |
Informations obtained from electrical transport measurements are limited in the sense that they provide information only about the conductance properties of a material system. Rich physics lies underneath several physical properties of a system- for example, if we want to probe the statistics of charge carriers (fermionic or bosonic) or the interactions persisting among charge carriers or even the number of charge carriers. Such informations are completely unavailable from transport measurements. Quantum shot noise and cross-correlations opens up the door for providing information about these physical aspects. Superconducting hybrid nanostructures are one of the building blocks for investigating noise and cross-correlations giving insight into the statistics and interactions among the charge carriers. Three-terminal superconducting hybrid nanostructures with all superconducting leads (S/N/S) exhibit Multiple Andreev Reflection (MAR) enhancing the level of very sensitive noise and cross-correlations. The cross-correlation measurements in a double S/N/S junction have been performed for the first time till date with a very sensitive three-SQUID assembly inside the dilution refrigerator acting as a current amplifier. Both positive and negative sign of cross-correlation have been obtained in different bias regimes within the superconducting gap making this device as a potential solid state entangler for on-demand generation of entangled electrons. Thus a fermionic analogue of optical Hanbury-Brown and Twiss experiment has been successfully realized. Proposal for a Cooper-pair splitter with quantum dots (QD) in a three-terminal geometry is made due to the higher splitting efficiency on account of higher charging energy in QD’s. In this context transport properties of Quantum dots connected to superconducting and normal reservoir, especially the signature of Andreev Bound States are presented.
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