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.

Bouncing states in quantum dots

Abstract: We observe sequences of asymmetric Coulomb blockade resonances in the conductance of a closed quantum dot. Around a symmetric peak at the center of such a sequence, several asymmetric resonances with a steep flank facing the central peak are found. This effect occurs for an average coupling of the quantum dot states to the leads which is of the order of both their average energy level spacing as well as of the thermal energy. These observations are interpreted in terms of a single state (``bouncing state'') that couples particularly well to the leads. Such a state can influence the line shapes of several neighboring Coulomb blockade resonances.

Stored energy in irradiated NaCl

Abstract: In this paper we describe the development of stored energy in pure and doped NaCl samples as well as natural rock salt during irradiation. The dependencies of the stored energy value on the irradiation temperature and the presence of dopants have been studied. Irradiation experiments at controlled temperatures between 50 and 150°C and doses up to 150 Grad have been carried out. For pure NaCl we have found that the damage is formed only in a relatively narrow range of irradiation temperatures. In almost all cases the effect of doping is that the stored energy value is larger and the temperature range where stored energy develops is wider as compared to pure NaCl.

Electron cascade for distant spin readout.

Abstract: The spin of a single electron in a semiconductor quantum dot provides a well-controlled and long-lived qubit implementation. The electron charge in turn allows control of the position of individual electrons in a quantum dot array, and enables charge sensors to probe the charge configuration. Here we show that the Coulomb repulsion allows an initial charge transition to induce subsequent charge transitions, inducing a cascade of electron hops, like toppling dominoes. A cascade can transmit information along a quantum dot array over a distance that extends by far the effect of the direct Coulomb repulsion. We demonstrate that a cascade of electrons can be combined with Pauli spin blockade to read out distant spins and show results with potential for high fidelity using a remote charge sensor in a quadruple quantum dot device. We implement and analyse several operating modes for cascades and analyse their scaling behaviour. We also discuss the application of cascade-based spin readout to densely-packed two-dimensional quantum dot arrays with charge sensors placed at the periphery. The high connectivity of such arrays greatly improves the capabilities of quantum dot systems for quantum computation and simulation.

Changes in Microstructural and Mechanical Properties of AISI Type 316LN Stainless Steel and Modified 9Cr-1Mo Steel on Long-Term Exposure to Flowing Sodium in a Bi-Metallic Sodium Loop

Abstract: AISI Type 316LN stainless steel (SS) and modified 9Cr-1Mo steel were exposed to flowing sodium at 798 K (525 °C) for 30000 hours in a bi-metallic sodium loop. The changes in microchemical, microstructural, and mechanical properties were evaluated and compared with the as-received and thermally aged specimens. Effective carbon diffusion coefficient $$ {\left( {D_{\text{C}}^{\text{eff}} } \right)} $$ was calculated to be 6.8 × 10−19 m2/s. Depth of carburization analyzed by secondary ion mass spectroscopy technique was around 100 µm for sodium-exposed 316LN SS. Selective leaching of nickel occurred across depth from the surface of sodium-exposed 316LN SS with the formation of 10 µm ferrite layer, and it showed an increase in yield strength by 15 pct, reduction in ductility by 60 pct, and a decrease in impact energy by 15 pct vis-a-vis the as-received and thermally aged specimens. This reduction in ductility occurred due to extensive precipitation of sigma phase as a result of long-term thermal aging. No significant changes were observed in the sodium/modified 9Cr-1Mo steel interfacial microstructure as well as tensile properties of sodium-exposed modified 9Cr-1Mo steel. Although modified 9Cr-1Mo neither showed carburization nor decarburization on sodium exposure, it showed a drastic reduction in the impact strength, which was attributed to the presence of Laves phase, observed in X-ray diffraction patterns.