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.

Effect of co-substitution of La/Li on structure, microstructure, dielectric and piezoelectric behavior of Bi 0.50 Na 0.50 TiO 3 ceramics

Abstract: Polycrystalline specimens with compositions x = 0.04 and y ≤ 0.10 in (Bi1−xLax)0.5(Na1−yLiy)0.5TiO3 system are synthesized by semi-wet technique. Structure, microstructure, dielectric and piezoelectric properties are investigated in order to observe the effect of co-substitution of La/Li ions on A-sites of BNT ceramic system. Rietveld analysis of X-ray diffraction data for all the specimens reveals single phase formation with rhombohedral structure. Microstructures of these specimens indicate a decrease in grain size with homogeneous grain growth up to y ≤ 0.075 followed by anomalous grain growth for y = 0.100. The temperature dependence of dielectric plots exhibits a broad maximum whose position (T m ) is frequency dependent up to y ≤ 0.075. A switching from frequency dependent to frequency independent dielectric behaviour is observed with increasing Li concentration. All the samples show nearly saturated P–E loop at room temperature. The composition x/y = 0.04/0.025 exhibits improved ferroelectric with P r = 29.26 µC/cm2 and piezoelectric constant of d 33 = 70 pC/N.

High-energy electronic interaction in the 3 d band of high-temperature iron-based superconductors

Abstract: One of the most unique and robust experimental facts about iron-based superconductors is the renormalization of the electronic band dispersion by factor of 3 and more near the Fermi level. Obviously related to the electron pairing, this prominent deviation from the band theory lacks understanding. Experimentally studying the entire spectrum of the valence electrons in iron arsenides, we have found an unexpected depletion of the spectral weight in the middle of the iron-derived band, which is accompanied by a drastic increase of the scattering rate. At the same time, the measured arsenic-derived band exhibits very good agreement with theoretical calculations. We show that the low-energy Fermi velocity renormalization should be viewed as a part of the modification of the spectral function by a strong electronic interaction. Such an interaction with an energy scale of the whole $d$ band appears to be a hallmark of many families of unconventional superconductors.