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Related papers: Effect of K Doping on Phonons in Ba1-xKxFe2As2

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The effect of pressure on the zone-center optical phonon modes of antimony in the A7 structure has been investigated by Raman spectroscopy. The A_g and E_g frequencies exhibit a pronounced softening with increasing pressure, the effect…

Other Condensed Matter · Physics 2009-11-11 X. Wang , K. Kunc , I. Loa , U. Schwarz , K. Syassen

BaNi$_2$As$_2$ is a nonmagnetic analogue of the iron pnictide superconductors, and in its tetragonal state exhibits an incommensurate charge-density-wave (IC-CDW) and a sizable elastoresistance. In this work, phonons in BaNi$_2$As$_2$…

We report density functional calculations based on local density approximation (LDA) of the properties of doped barium bismuthates. Using linear-response approach developed in the framework of the linear muffin-tin-orbital method the phonon…

Superconductivity · Physics 2007-05-23 V. Meregalli , S. Y. Savrasov

We present neutron inelastic scattering measurements of the low-energy phonons in single crystal BiFeO3. The dispersions of the three acoustic phonon modes (LA along [100], TA1 along [010] and TA2 along [110]) and two low energy optic…

Raman and infrared absorption spectra of Mg(1-x)Al(x)B(2) have been collected for 0<x<0.5 in the spectral range of optical phonons. The x-dependence of the peak frequency, the width and the intensity of the observed Raman lines has been…

Superconductivity · Physics 2009-11-07 P. Postorino , A. Congeduti , P. Dore , A. Nucara , A. Bianconi , D. Di Castro , S. De Negri , A. Saccone

Stimulated small-angle light scattering was used to measure the structure factor of a Bose-Einstein condensate in the phonon regime. The excitation strength for phonons was found to be significantly reduced from that of free particles,…

Condensed Matter · Physics 2016-08-15 D. M. Stamper-Kurn , A. P. Chikkatur , A. Görlitz , S. Inouye , S. Gupta , D. E. Pritchard , W. Ketterle

The dynamics of an exciton-LO-phonon system after an ultrafast optical excitation in an InAs/GaAs quantum dot is studied theoretically. Influence of anharmonic phonon damping and its interplay with the phonon dispersion is analyzed. The…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Pawel Machnikowski , Lucjan Jacak

Inelastic neutron scattering is used to measure the temperature dependent phonon dispersion in Ca$_{2-x}$Sr$_{x}$RuO$_{4}$ ($x=0.4$, 0.6). The in-plane $\Sigma_{4}$ octahedral tilt mode softens significantly at the zone boundary of the high…

Strongly Correlated Electrons · Physics 2015-05-13 R. G. Moore , M. D. Lumsden , M. B. Stone , Jiandi Zhang , Y. Chen , J. W. Lynn , R. Jin , D. Mandrus , E. W. Plummer

We have measured the room-temperature phonon spectrum of Mo-stabilized $\gamma-$U. The dispersion curves show unusual softening near the H point, q=[1/2,1/2,1/2], which may derive from the metastability of the $\gamma-$U phase or from…

The doping dependence of the micro-Raman spectra of high quality La_{2-x}Sr_xCuO_4 microcrystals with x=0.0-0.45 has been investigated in the region 10-300 K. The phonon at ~100 cm^{-1} of the orthorhombic phase shows a classical soft mode…

Superconductivity · Physics 2009-11-13 D. Lampakis , E. Liarokapis , C. Panagopoulos

We analyze the influence of phonons on the d-wave pairing instability in the Hubbard model on the two-dimensional square lattice at weak to moderate interaction U, using a functional renormalization group scheme with frequency-dependent…

Strongly Correlated Electrons · Physics 2013-05-29 Carsten Honerkamp , Henry C. Fu , Dung-Hai Lee

Temperature and composition dependences of high-energy longitudinal optical (LO) phonons in YBa2Cu3O{6+x}, studied by inelastic neutron scattering measurements, provide clear evidence for temperature dependent spatial inhomogeneity of doped…

Superconductivity · Physics 2007-05-23 Y. Petrov , T. Egami , R. J. McQueeney , M. Yethiraj , H. A. Mook , F. Dogan

In this paper we present a theoretical analysis of the effect of magnetostriction on quantum oscillations of elastic constants in metals under strong magnetic fields. It is shown that at low temperatures a significant softening of some…

Materials Science · Physics 2016-08-31 Natalya A. Zimbovskaya

Phonon spectra of detwinned {SrFe$_2$As$_2$} crystals, as measured by inelastic x-ray scattering, show clear anisotropy accompanying the magneto-structural transition at 200 K. We model the mode splitting using magnetic DFT calculations,…

The Fe K X-ray absorption near edge structure (XANES) of BaFe2-xCoxAs2 superconductors was investigated. No appreciable alteration in shape or energy position of this edge was observed with Co substitution. This result provides experimental…

In this paper, the effect of B and N doping on the phonon induced thermal conductivity of graphene has been investigated. This study is important when one has to evaluate the usefulness of electronic properties of B and N doped graphene. We…

We present a detailed study of a phonon-assisted incoherent excitation mechanism of single quantum dots. A spectrally-detuned laser couples to a quantum dot transition by mediation of acoustic phonons, whereby excitation efficiencies up to…

Optics · Physics 2015-06-05 S. Weiler , A. Ulhaq , C. Roy , S. M. Ulrich , D. Richter , M. Jetter , S. Hughes , P. Michler

Recent laser angle-resolved photoemission spectroscopy studies have established the presence of a new kink in the low-energy nodal dispersion of Bi$_2$Sr$_2$CaCu$_2$O$+{8+\delta}$ (Bi-2212). The energy scale (~8-15 meV) of this kink appears…

We performed temperature- and doping-dependent high-resolution Raman spectroscopy experiments on YBa$_2$Cu$_3$O$_{7-\delta}$ to study $B$$_{\rm 1g}$ phonons. The temperature dependence of the real part of the phonon self-energy shows a…

We have performed Raman scattering measurements on BiFeO3 nanoparticles and studied both magnetic and lattice modes. We reveal strong anomalies between 140 K and 200 K in the frequency of magnon and E(LO1), E(TO1) and A1(LO1) phonon modes.…