Solid State Physics Laboratory

About: Solid State Physics Laboratory is a facility organization based out in Delhi, India. It is known for research contribution in the topics: Quantum dot & Dielectric. The organization has 1754 authors who have published 2597 publications receiving 50601 citations.

Mercury-enhanced high Tc in the Bi (Pb)SrCaCuO system

Abstract: This short communication reports an onset Tc as high as 135 K and a Tc0 (zero resistivity) of 114 K in a Bi1.7Pb0.3Sr2−xHgxCa2Cu3Oy composition. Mercury does not seem to be incorporated in the lattice. It appears probable that mercury enhances the oxidation state of copper in the CuO2 layers and thus raises the Tc. Very interestingly, the XRD spectra of these specimens show the presence of only one phase, that is, the 2212 phase of the Bi-system. Highest value of Tc0 (114 K) was consistently found for Hg=0.3, even when the entire series of specimens was prepared four times under identical conditions. The studies hint at the possibilities of obtaining Tc values higher than the standard assigned Tc values to various oxide superconductors.

Radiation damage in NaCl. III. Melting phenomena of sodium colloids

Abstract: We report measurements on the melting behavior of colloids produced in irradiated NaCl. With differential scanning calorimetry (DSC) several latent-heat peaks near the melting temperature of pure bulk sodium metal have been detected. It appears that the total latent heat in these peaks is an accurate measure of the amount of damage in the crystal. Peak temperature and shape provide more detailed information about the properties of the colloids. The different melting temperatures can be explained by differences in the typical sizes of the colloid, based on the theory for melting of small particles. This DSC technique provides a method to evaluate the production of radiation damage in detail without changing the properties of the damaged crystal.

Josephson Junctions with Tunable Weak Links

Abstract: The electrical properties of organic molecular crystals, such as polyacenes or C60, can be tuned from insulating to superconducting by application of an electric field. By structuring the gate electrode of such a field-effect switch, the charge carrier density, and therefore also the superfluid density, can be modulated. Hence, weak links that behave like Josephson junctions can be fabricated between two superconducting regions. The coupling between the superconducting regions can be tuned and controlled over a wide range by the applied gate bias. Such devices might be used in superconducting circuits, and they are a useful scientific tool to study superconducting material parameters, such as the superconducting gap, as a function of carrier concentration or transition temperature.

Nanosecond-timescale spin transfer using individual electrons in a quadruple-quantum-dot device

Abstract: The ability to coherently transport electron-spin states between different sites of gate-defined semiconductor quantum dots is an essential ingredient for a quantum-dot-based quantum computer. Previous shuttles using electrostatic gating were too slow to move an electron within the spin dephasing time across an array. Here, we report a nanosecond-timescale spin transfer of individual electrons across a quadruple-quantum-dot device. Utilizing enhanced relaxation rates at a so-called hot spot, we can upper bound the shuttle time to at most 150 ns. While actual shuttle times are likely shorter, 150 ns is already fast enough to preserve spin coherence in, e.g., silicon based quantum dots. This work therefore realizes an important prerequisite for coherent spin transfer in quantum dot arrays.