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.

Point-contact spectroscopy in MgB2: from fundamental physics to thin-film characterization

Abstract: In this paper we highlight the advantages of using point-contact spectroscopy (PCS) in multigap superconductors like MgB2, both as a fundamental research tool and as a non-destructive diagnostic technique for the optimization of thin-film characteristics. We first present some results of crucial fundamental interest obtained by directional PCS in MgB2 single crystals, for example the temperature dependence of the gaps and of the critical fields, and the effect of a magnetic field on the gap amplitudes. Then, we show how PCS can provide useful information about the surface properties of MgB2 thin films (e.g., Tc, gap amplitude(s), clean-?or dirty-limit conditions) in view of their optimization for the fabrication of tunnel and Josephson junctions for applications in superconducting electronics.

Local backscattering in the quantum Hall regime

Abstract: A two-dimensional electron gas in the quantum Hall regime has been investigated by tuning the local potential with the metallic tip of a scanning force microscope. The longitudinal four-terminal resistance of the Hall bar structure was recorded while the tip was scanned above. The resulting resistance images exhibit local features that show a $1∕B$-periodicity. These features line up along the Hall bar edges resembling the formation of edge channels. At certain filling factors they develop a subtle fine structure indicating the intricate microscopic variations of states in real space.

The relevance of electrostatics for scanning-gate microscopy

Abstract: Scanning-probe techniques have been developed to extract local information from a given physical system In particular, conductance maps obtained by means of scanning-gate microscopy (SGM), where a conducting tip of an atomic-force microscope is used as a local and movable gate, seem to present an intuitive picture of the underlying physical processes Here, we argue that the interpretation of such images is complex and not very intuitive under certain circumstances: scanning a graphene quantum dot (QD) in the Coulomb-blockaded regime, we observe an apparent shift of features in scanning-gate images as a function of gate voltages, which cannot be a real shift of the physical system Furthermore, we demonstrate the appearance of more than one set of Coulomb rings arising from the graphene QD We attribute these effects to screening between the metallic tip and the gates Our results are relevant for SGM on any kind of nanostructure, but are of particular importance for nanostructures that are not covered with a dielectric, eg graphene or carbon nanotube structures

Effect of Sm on dielectric, ferroelectric and piezoelectric properties of BPTNZ system

Abstract: Study on structural, dielectric and ferroelectric properties of Sm substituted BPTNZ system with compositional formula Ba0.80−xSmxPb0.20Zr0.10Ti0.90O3+0.5% Nb2O5 by weight, (x=0 to 0.01 in the steps of 0.0025) was done. Conventional solid state method was adopted for the synthesis of the samples. The single phase was confirmed by X-ray diffraction (XRD) analysis. Scanning electron microscopy was done for microstructural analysis. The dielectric properties were measured as a function of temperature and frequency. Ferroelectric P–E loops were recorded for all the samples at room temperature. Piezoelectric parameters such as ‘d33’ and electromechanical coupling coefficient ‘kp’ were also measured at room temperature for all the samples. The relationship between properties and structure of the prepared ceramics was established and results are discussed here.