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.

High-temperature superconductivity in lattice-expanded C60.

Abstract: C60 single crystals have been intercalated with CHCl3 and CHBr3 in order to expand the lattice. High densities of electrons and holes have been induced by gate doping in a field-effect transistor geometry. At low temperatures, the material turns superconducting with a maximum transition temperature of 117 K in hole-doped C60/CHBr3. The increasing spacing between the C60 molecules follows the general trend of alkali metal–doped C60 and suggests routes to even higher transition temperatures.

Strongly reduced band gap in a correlated insulator in close proximity to a metal

Abstract: Using a combination of photoelectron and inverse photoelectron spectroscopy, we show that the band gap in a monolayer of C60 on a Ag surface is strongly reduced from the solid C60 surface value. We argue that this is a result of the reduction of the on-site molecular Coulomb interaction due to the influence of image charges in the metal substrate. This result suggests that the physical properties of correlated insulators and semiconductors will be strongly modified if prepared in ultra thin form on metal substrates or sandwiched between metal layers.

Quantum capacitance and density of states of graphene

Abstract: We report on measurements of the quantum capacitance in graphene as a function of charge carrier density. A resonant LC-circuit giving high sensitivity to small capacitance changes is employed. The density of states, which is directly proportional to the quantum capacitance, is found to be significantly larger than zero at and around the charge neutrality point. This finding is interpreted to be a result of potential fluctuations with amplitudes of the order of 100 meV in good agreement with scanning single-electron transistor measurements on bulk graphene and transport studies on nanoribbons.

Spin States in Graphene Quantum Dots

Abstract: We investigate ground and excited state transport through small (d≈70 nm) graphene quantum dots. The successive spin filling of orbital states is detected by measuring the difference between ground-state energies as a function of a magnetic field. For a magnetic field in-plane of the quantum dot the Zeeman splitting of spin states is measured. The results are compatible with a g factor of 2, and we detect a spin-filling sequence for a series of states which is reasonable given the strength of exchange interaction effects expected by comparing Coulomb interaction energy and kinetic energy of charge carriers in graphene.