Related papers: Raman Studies in MgB2-xCx
Point-contact measurements on the carbon-substituted Mg(B$_{1-x}$C$_x$)$_2$ filament/powder samples directly reveal a retention of the two superconducting energy gaps in the whole doping range from $x = 0$ to $x \approx 0.1$. The large gap…
The non-dispersed soft x-ray emission from a La/B4C periodic multilayer irradiated by monochromatic x-rays has been measured as a function of the incident photon energy in the 125-200 eV range for different scattering angles. We have…
We study phonons in MgB2 using inelastic x-ray scattering (1.6 and 6 meV resolution). Our measurements show excellent agreement with theory for the dispersion and line-width: we clearly observe the softening and broadening of the crucial…
Here we report synthesis and characterization of Mg_{1-x}Sc_{x}B_{2} (0.12<x<0.27) system, with critical temperature in the range of 30>T_{c}>6 K. We find that the Sc doping moves the chemical potential through the 2D/3D electronic…
The recently discovered layered BiS2-based superconductors have attracted a great deal of interest due to their structural similarity to cuprate and iron-pnictide superconductors. We have performed Raman scattering measurements on two…
We revisit here how Raman spectroscopy can be used to estimate the H content in hard hydrogenated amorphous carbon layers. The H content was varied from 2 at.% to 30 at.%, using heat treatments of a a-C:H, from room temperature to 1300 K…
Experimentally, Raman continuum for $A_g$ and $B_g$ geometry exhibits peaks far apart from each other (about 80 to 150 $\rm cm^{-1}$) in frequency. The former is insensitive to doping over a small range where $T_c$ does not vary much…
We report that the ternary MgB2-xCx compounds adopt an isostructural AlB2-type hexagonal structure in a relatively small range of nominal carbon concentration, x<0.1. The lattice parameter a decreases almost linearly with increasing carbon…
Infrared absorption measurements in the range of 125 to 700 cm^(-1) have been carried out as a function of temperature upto 5 K in MgB2. The absorption spectrum is characterised by a broad band centred at 485 cm^{-1}, with shoulders at 333…
Resonance Raman scattering, which probes electrons, phonons and their interplay in crystals, is extensively used in two-dimensional materials. Here we investigate Raman modes in MoSe$_2$ at different laser excitation energies from 2.33 eV…
Low energy optical modes of MBE-grown In1-xGaxN thin films with different values of x are investigated using Raman spectroscopy. We also studied the influence of Raman excitation frequency using red and green lasers on scattering intensity…
The band structure of bilayer graphene is tunable by introducing a relative twist angle between the two layers, unlocking exotic phases, such as superconductor and Mott insulator, and providing a fertile ground for new physics. At…
Temperature dependent Raman scattering studies in polycrystalline MgB2(10<T<300 K)reveal that the E2g phonon does not experience any self energy renormalization effect across the superconducting critical temperature Tc ~ 40 K. In contrast,…
We present low-temperature Raman measurements on gate tunable graphene encapsulated in hexagonal boron nitride, which allows to study in detail the Raman G and 2D mode frequencies and line widths as function of the charge carrier density.…
We study the effects of C substitutions in MgB_2 within the two-band model in the Eliashberg formulation. We use as input the B-B stretching-mode frequency and the partial densities of states N_{sigma}(EF) and N_{pi}(EF), recently…
It is shown that the sharp peak in the $E_{2g}$ Raman spectrum of superconducting $MgB_2$ is due to a bound state caused by the electron-phonon coupling. Our theory explains why this peak appears only in the spectra with $E_{2g}$ symmetry…
We report generation of cascaded rotational Raman scattering up to 58th orders in coherently excited CO_2 molecules. The high-order Raman scattering, which produces a quasiperiodic frequency comb with more than 600 sidebands, is obtained…
The Raman spectra of the parent compound NaxCoO2 (x=0.75) and the superconducting oxyhydrates NaxCoO2.yH2O with different superconducting temperatures (Tc) have been measured. Five Raman active phonons around 195 cm-1 (E1g), 482 cm-1, 522…
Neutron powder diffraction has been used to characterize a sample of C-substituted MgB2 synthesized from Mg and B4C (with isotopically enriched 11B). The sample is multiphase, with the major phase [73.4(1) wt.%] being Mg(B1-xCx)2 with…
The optical conductivity of MgB$_2$ has been determined on a dense polycrystalline sample in the spectral range 6 meV - 4.6 eV using a combination of ellipsometric and normal incidence reflectivity measurements. $\sigma_{1}(\omega)$…