相关论文: Phonons in MgB2 by Polarized Raman Scattering on S…
Electronic Raman scattering studies on MgB2 single crystals as a function of excitation and polarization have revealed three distinct superconducting features: a clean gap below 37 cm-1 and two coherence peaks at 109 cm-1 and 78 cm-1 which…
Room temperature Raman scattering measurements have been carried out on well characterized samples of MgB2-xCx. The Raman line corresponding to the E2g phonon mode shows progressive hardening from 620 cm-1 in pristine MgB2 to 775 cm-1 in…
We present a Raman scattering study of the E2g phonon anharmonicity and of superconductivity induced self-energy effects in MgB2 single crystals. We show that anharmonic two phonon decay is mainly responsible for the unusually large…
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 performed comparable polarized Raman scattering studies of MoTe2 and WTe2. By rotating crystals to tune the angle between the principal axis of the crystals and the polarization of the incident/scattered light, we obtained the angle…
Phonon spectra have been investigated by micro-Raman scattering from 290 to 20K. New peaks at 500 and 674 cm-1 appear below 250K in MgB2. These peaks are explained by the Fermi resonance, where Raman-active E2g intereacts with the overtone…
We report Raman spectra and synchrotron x-ray diffraction measurements of lattice parameters of polycrystalline MgB2 under hydrostatic pressure conditions up to 15 GPa. An anomalously broadened Raman band at 620 cm-1 is observed that…
The paper presents polarized Raman scattering study on a few-micron-size crystallite of LiBC with natural faces. The experiment on as grown sample has revealed a four lattice modes with frequencies at 1276 cm^-1, 830 cm^-1, 546 cm^-1 and…
We measure phonon dispersion and linewidth in a single crystal of MgB_2 along the Gamma-A, Gamma-M and A-L directions using inelastic X-Ray scattering. We use Density Functional Theory to compute the effect of both electron-phonon coupling…
Raman spectra of the MgB2 ceramic samples were measured as a function of pressure up to 32 GPa at room temperature. The spectrum at normal conditions contains a very broad peak at ~590 cm-1 related to the E2g phonon mode. The frequency of…
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…
Polarized Raman scattering measurements on IrTe$_2$ single crystals carried out over 15~K - 640~K temperature range, and across the structural phase transition, reveal new insights regarding the crystal symmetry.\ In the high temperature…
The effect of pressure on optical phonon frequencies of MgB$_2$ has been calculated using the frozen-phonon approach based on a pseudopotential method. Gr\"uneisen parameters of the harmonic mode frequencies are reported for the…
The polarized Raman scattering spectra from freshly cleaved $ab$, $ac$, and $bc$ surfaces of high quality twin free YBa$_2$Cu$_3$O$_{6.5}$ (Ortho-II) single crystals ($T_c$=57.5 K and $\Delta T = 0.6$ K) were studied between 80 and 300 K.…
Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_{3}$ is one of the simplest representatives of the class of lead relaxors and often serves as a model system for more complicated compounds. In this paper we analyse both polarized and depolarized Raman scattering…
We have measured polarized Raman scattering spectra of the Fe$_{1-x}$Co$_{x}$Sb$_{2}$ and Fe$_{1-x}$Cr$_{x}$Sb$_{2}$ (0$\leq x\leq $0.5) single crystals in the temperature range between 15 K and 300 K. The highest energy $B_{1g}$ symmetry…
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…
We have performed polarized Raman scattering measurements on WTe$_2$, for which an extremely large positive magnetoresistance has been reported recently. We observe 5 A$_1$ phonon modes and 2 A$_2$ phonon modes out of 33 Raman active modes,…
We investigated polarization dependence of the Raman modes in black phosphorus (BP) using five different excitation wavelengths. The crystallographic orientation was determined by comparing polarized optical microscopy with high-resolution…
Polarized Raman scattering measurements have been performed on Na0.5CoO2 single crystal from 8 to 305 K. Both the A1g and E1g phonon modes show a softening below Tc1 ~ 83 K. Additionally, the A1g phonon mode, which is forbidden in the…