The electrodynamic response of the heavy fermion compound CeCoIn5 is studied via infrared spectroscopy. Below 100 K the high temperature Drude-like conductivity evolves into two distinct components. At low energies a narrow mode is observed which is characteristic of the response of heavy quasiparticles. At higher energies a gap structure emerges with 2D;600 cm ~75 meV!. Examination of the fine...

We investigated optical properties of Pr0.5Sr0.5MnO3, which has the Atype antiferromagnetic ordering at a low temperature. We found that T dependence of spectral weight transfer shows a clear correlation with the magnetic phase transition. In comparison with the optical conductivity results of Nd0.5Sr0.5MnO3, which has the CE-type antiferromagnetic charge ordering, we showed that optical proper...

Perovskite CH3NH3PbI3 exhibits outstanding photovoltaic performances, but the understanding of the atomic motions remains inadequate even though they take a fundamental role in transport properties. Here, we present a complete atomic dynamic picture consisting of molecular jumping rotational modes and phonons, which is established by carrying out high-resolution time-of-flight quasi-elastic and...

Polyaniline is a widely studied conducting polymer and is a useful material in its bulk and thin film form for many applications, because of its excellent optical and electrical properties. Pristine and iodine doped polyaniline thin films were prepared by a.c. and rf plasma polymerization techniques separately for the comparison of their optical and electrical properties. Doping of iodine was e...

The real-time dynamics of interacting electrons out of equilibrium contains detailed microscopic information about electronically correlated materials, which can be read out with time-resolved optical spectroscopy. The reflectivity that is typically measured in pump-probe experiments is related to the nonequilibrium optical conductivity. We show how to express this quantity in terms of real-tim...

We discuss how to analyze the optical conductivity and Raman spectra of multiorbital systems using the velocity and the Raman vertices in a similar way Raman vertices were used to disentangle nodal and antinodal regions in cuprates. We apply this method to iron superconductors in the magnetic and nonmagnetic states, studied at the mean-field level. We find that the anisotropy in the optical con...

We discuss some recent results for the properties of doped antiferromagnets, obtained within the planar t-J model mainly by the finite-temperature Lanczos method, with the emphasis on the comparison with experimental results in cuprates. Among the thermodynamic properties the chemical potential and entropy are considered, as well as their relation to the thermoelectric power. At the intermediat...

Inverse Fourier Transform of optical conductivity is used for studies of quasiparticle relaxation in Heavy Fermions in time domain. We demonstrate the usefulness of the procedure on model spectra and then use it to study quasiparticle relaxation in two Heavy Fermions YbFe4Sb12 and CeRu4Sb12. Optical conductivity in time domain reveals details of quasiparticle relaxation close to the Fermi level...

In this work, we study the controlled doping of thin films of substituted nickel phthalocyanine, NiPcR8, where R=-SC6H13, with anthracene and TCNQ and investigate the effects of the extent of this doping on the optical and electrical properties of NiPcR8 films. Optical constants, namely index of refraction (n) and extinction coefficient (k) have increased for both types of doping, as determined...

We have investigated the temperature dependence of the optical conductivity of GdRu4P12, which shows an antiferromagnetic ordering below TN 1⁄4 22K. Above TN, the optical conductivity spectra exhibit a Drude-like feature due to the free carriers. However, below TN a new peak was found to develop around 30meV in addition to the narrowing of the Drude component. We assigned this peak to the elect...