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The temperature evolution of the resonant Raman scattering from high-quality bilayer 2H-MoS$_{2}$ encapsulated in hexagonal BN flakes is presented. The observed resonant Raman scattering spectrum as initiated by the laser energy of 1.96 eV,…

The electron-phonon interaction is of central importance for the electrical and thermal properties of solids, and its influence on superconductivity, colossal magnetoresistance, and other many-body phenomena in correlated-electron materials…

The vibrational properties of 2H-TaSe$_{2-x}$S$_x$ ($0 \le x \le 2$) single crystals were probed using Raman spectroscopy and density functional theory calculations. The end members revealed two out of four symmetry-predicted Raman active…

We report plane-polarized Raman scattering spectra of iron oxypnictide superconductor NdFeAsO$_{1-x}$F$_x$ single crystals with varying fluorine $x$ content. The spectra exhibit sharp and symmetrical phonon lines with a weak dependence on…

Superconductivity · Physics 2009-11-13 Y. Gallais , A. Sacuto , M. Cazayous , P. Cheng , L. Fang , H. H. Wen

Phonon properties of $\mathrm{Mo_3Sb_{7-x}Te_x}$ ($x=0,1.5, 1.7$), a potential high-temperature thermoelectric material, have been studied with inelastic neutron and x-ray scattering, and with first-principles simulations. The substitution…

Materials Science · Physics 2015-12-11 Dipanshu Bansal , Chen W. Li , Ayman H. Said , Douglas L. Abernathy , Jiaqiang Yan , Olivier Delaire

We have used polarized Raman scattering to probe lattice vibrations and charge ordering in 12 nm thick, epitaxially strained PrNiO$_3$ films, and in superlattices of PrNiO$_3$ with the band-insulator PrAlO$_3$. A carefully adjusted confocal…

Strongly Correlated Electrons · Physics 2015-06-23 M. Hepting , M. Minola , A. Frano , G. Cristiani , G. Logvenov , E. Schierle , M. Wu , M. Bluschke , E. Weschke , H. U. Habermeier , E. Benckiser , M. Le Tacon , B. Keimer

We report the evolution of charge density wave states under pressure for two NbS3 phases triclinic (phase I) and monoclinic (phase II) at room temperature. Raman and X-ray diffraction (XRD) techniques are applied. The x-ray studies on the…

To investigate the pressure-induced structural transitions of chromium dioxide (CrO$_{2}$), phonon dispersions and total energy band structures are calculated as a function of pressure. The first structural transition has been confirmed at…

Materials Science · Physics 2012-05-17 Sooran Kim , Kyoo Kim , Chang-Jong Kang , B. I. Min

Radio-frequency compressed ultrafast electron diffraction has been used to probe the coherent and incoherent coupling of impulsive electronic excitation at 1.55 eV (800 nm) to optical and acoustic phonon modes directly from the perspective…

Materials Science · Physics 2015-06-23 Robert P. Chatelain , Vance R. Morrison , Bart L. M. Klarenaar , Bradley J. Siwick

Group III nitride based two-dimensional multi-quantum well (MQW) nanostructures find remarkable applications in the visible to ultraviolet light sources. The interface optical (IFO) phonon modes in a c-axis oriented superlattice of…

We report on the lattice and spin dynamics in the monopnictide CrAs using polarized Raman scattering. This system exhibits a first-order magneto-structural phase transition at T_N~ 265 K, below which the magnetic moments of Cr form an…

Materials Science · Physics 2019-10-07 K. Sen , Y. Yao , R. Heid , A. Omoumi , F. Hardy , K. Willa , M. Merz , A. A. Haghighirad , M. Le Tacon

1LO optical phonons in free-standing mixed Cd1-xZnxS nanocrystals, synthesized using chemical precipitation, are investigated using Raman spectroscopy. As expected for the nanocrystals, the 1-LO modes are found to appear at slightly lower…

Materials Science · Physics 2009-05-05 Satyaprakash Sahoo , S. Dhara , V. Sivasubramanian , S. Kalavathi , A. K. Arora

We report a comparative Raman spectroscopic study of the quasi-one-dimensional charge-density-wave systems \ab (A = K, Rb). The temperature and polarization dependent experiments reveal charge-coupled vibrational Raman features. The…

Strongly Correlated Electrons · Physics 2009-11-13 D. M. Sagar , D. Fausti , S. Yue , C. A. Kuntscher , S. van Smaalen , P. H. M. van Loosdrecht

Alloyed MnxZn1_xPS3 samples have been grown covering the whole compositional range and studied by means of Raman spectroscopy at temperatures covering from 4K up to 850K. Our results, supported by SQUID magnetic measurements, allowed, from…

Understanding the coupling between lattice vibrations and magnetic order is crucial for controlling properties of two-dimensional magnetic materials. Here, we investigate the vibrational properties of bulk and thick-flake CrCl$_\textrm{3}$…

Intermediate frequency range (511 - 514 cm-1) Si phonons in Si-SiO2 nanocomposites are shown to have contribution from both core1 and surface/interface1 Si phonons, where, ratio of contribution of the two depends on the size of a Si…

Mesoscale and Nanoscale Physics · Physics 2015-03-13 Ekta Rani , Alka Ingale , A. Chaturvedi , M. P. Joshi , L. M. Kukreja

We report the dispersion measurements, using angle-resolved reflection electron-energy-loss-spectroscopy (AREELS), on two-dimensional (2D) plasmons in single and multilayer graphene which couple strongly to surface optical phonon (FK…

Mesoscale and Nanoscale Physics · Physics 2010-05-03 Yu Liu , Roy F. Willis

The crystal structure and phonon dynamics of pentacene is computed with the Quasi Harmonic Lattice Dynamics (QHLD) method, based on atom-atom potential. We show that two crystalline phases of pentacene exist, rather similar in thermodynamic…

Raman scattering in the spin-crossover system [Fe(pmd)(H2O){Au(CN)2}2]*H2O reveals a complex three-phase spin-state transition in contrast to earlier observations in magnetization measurements. We observe different spin state phases as…

Strongly Correlated Electrons · Physics 2010-03-09 V. Gnezdilov , P. Lemmens , P. Scheib , M. Ghosh , Yu. G. Pashkevich , H. Paulsen , V. Schuenemann , J. A. Wolny , G. Agusti , J. A. Real

We investigate exemplary the longitudinal optical (LO) mode order in compounds with a plasmon or plasmon-like phonon mode and additional phonon modes. When the oscillator strength of the plasmon or plasmon-like mode is gradually increased,…

Materials Science · Physics 2020-06-24 Thomas G. Mayerhöfer , Jürgen Popp