—Geant4 is a software toolkit for the simulation of the passage of particles through matter. It is used by a large number of experiments and projects in a variety of application domains, including high energy physics, astrophysics and space science, medical physics and radiation protection. Its functionality and mod-eling capabilities continue to be… (More)
Studies of the electromagnetic response of various classes of correlated electron materials including transition-metal oxides, organic and molecular conductors, intermetallic compounds with d and f electrons, as well as magnetic semiconductors are reviewed. Optical inquiry into correlations in all these diverse systems is enabled by experimental access to… (More)
We describe the electronic control of extraordinary terahertz transmission through subwavelength metal hole arrays fabricated on doped semiconductor substrates. The hybrid metal-semiconductor forms a Schot-tky diode structure, where the active depletion region modifies the substrate conductivity in real-time by applying an external voltage bias. This… (More)
Interacting conduction electrons are usually described within Fermi-liquid theory, which states that, in spite of strong interactions, the low-energy excitations are electron-like quasiparticles with charge and spin. In recent years there has been tremendous interest in conducting systems that are not Fermi liquids, motivated by the observation of highly… (More)
We studied the magnetic and electronic properties of the insulating charge-transfer salt (TMTTF) 2 AsF 6 by electron spin resonance (ESR), SQUID magnetometer and optical conductivity measurements. For the first time, the lattice dynamics was investigated in the vicinity of the charge order transition. We found a splitting of the electron-molecular-vibration… (More)
Controlling the dynamics of spins on surfaces is pivotal to the design of spintronic and quantum computing devices. Proposed schemes involve the interaction of spins with graphene to enable surface-state spintronics and electrical spin manipulation. However, the influence of the graphene environment on the spin systems has yet to be unravelled. Here we… (More)
The crystal structures of the quasi-one-dimensional organic salts (TMTTF) 2-PF 6 and (TMTSF) 2 PF 6 were studied by pressure-dependent x-ray diffraction up to 10 GPa at room temperature. The unit-cell parameters exhibit a clear anomaly due to a structural phase transition at 8.5 and 5.5 GPa for (TMTTF) 2 PF 6 and (TMTSF) 2 PF 6 , respectively.
Low-dimensional organic conductors could establish themselves as model systems for the investigation of the physics in reduced dimensions. In the metallic state of a one-dimensional solid, Fermi liquid theory breaks down and spin and charge degrees of freedom become separated. But the metallic phase is not stable in one dimension: as the temperature is… (More)