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.

Variation of lattice parameter with temperature and thermal expansion of the compound Cu2SnSe3

Abstract: The temperature variation of the lattice parameter of the compound Cu2SnSe3 has been studied in the temperature range 30 to 600°C by X-ray diffraction methods. The linear coefficient of thermal expansion at room temperature (30°C) is 20.4 × 10−6 deg−1 and it is found to decrease with increasing temperature. Die Temperaturanderung des Gitterparameters der Verbindung Cu2SnSe3 wurde im Temperaturbereich 30 bis 600°C durch Rontgenstrahlenbeugungsmethoden untersucht. Der lineare Koeffizient der thermischen Ausdehnung bei Zimmertemperatur (30°C) betragt 20,4 × 10−6 grd−1 und nimmt mit steigender Temperatur ab.

Interplay of fractional quantum Hall states and localization in quantum point contacts

Abstract: We investigate integer and fractional quantum Hall states in quantum point contacts (QPCs) of different geometries, defined in AlGaAs/GaAs heterostructures employing different doping and screening techniques. We find that even in the highest mobility samples, interference and localization strongly influence the transport properties. We propose microscopic models for these effects, based on single- and many-electron physics. For integer quantum Hall states, transport is modulated due to the self-consistent formation of compressible regions of enhanced or reduced density in the incompressible region of the constriction. In the fractional quantum Hall regime, we observe the localization of fractionally charged quasiparticles in the constriction and an interplay of single- and many-electron physics. At low electron densities and in comparatively weak magnetic fields, single-electron interference dominates transport. Utilizing optimized growth and gating techniques, the $\ensuremath{ u}=5/2$ state can be observed in a QPC, conserving the bulk properties in an unprecedented quality. Our results might improve the understanding of the influence of localization on the transmission properties of QPCs, which is necessary for the interpretation of interference experiments employing QPCs, especially at $\ensuremath{ u}=5/2$.

Inelastic x-ray scattering study of collective electron excitations in Mg B 2

Abstract: We report an experimental inelastic x-ray scattering study of the collective electron excitations in $\mathrm{Mg}{\mathrm{B}}_{2}$. Single-crystal and polycrystalline samples were used to study the free-electron-like $(\ensuremath{\sim}20\phantom{\rule{0.3em}{0ex}}\mathrm{eV})$ plasmon and the recently theoretically predicted low energy $(\ensuremath{\sim}3\phantom{\rule{0.3em}{0ex}}\mathrm{eV})$ plasmon mode. We present the energy-loss spectra for several momentum transfer values and find that the excitations exhibit a strong directional dependence. We discuss the dispersion of collective excitations and find a good agreement between the experimental results and the published theoretical calculations. Some discrepancies between the experimental data and the calculations were observed, namely slightly differing excitation energies and momentum-transfer dependence. However, these discrepancies are the same order of magnitude as the uncertainties within the various computational methods.