Related papers: Anomalous Phonons in CaFe2As2
The crystal structure and lattice phonons of (BEDT-TTF)_2I_3 superconducting \beta-phase are computed and analyzed by the Quasi Harmonic Lattice Dynamics (QHLD) method. Whereas the crystal structure and its temperature and pressure…
Polarization- and temperature-dependent Raman data along with theoretical simulations are presented for the Kagome ferromagnet Fe_3Sn_2. Eight out of nine expected phonon modes were identified. The experimental energies compare well with…
We formulate an ab initio downfolding scheme for electron-phonon coupled systems. In this scheme, we calculate partially renormalized phonon frequencies and electron-phonon coupling, which include the screening effects of high-energy…
We report an investigation of the lattice dynamical properties in a range of Fe$_{1+y}$Te$_{1-x}$Se$_{x}$ compounds, with special emphasis on the c-axis polarized vibration of Fe with B$_{1g}$ symmetry, a Raman active mode common to all…
The attempt to understand cuprate superconductors is complicated by the presence of multiple strong interactions. While many believe that antiferromagnetism is important for the superconductivity, there has been revived interest in the role…
The phonon density of states (DOS) and magnetic excitation spectrum of polycrystalline BiFeO$_3$ were measured for temperatures $200 \leq T \leq 750\,$K, using inelastic neutron scattering (INS). Our results indicate that the magnetic…
Recently colossal positive volume thermal expansion has been found in the framework compounds Ag3Co(CN)6 and Ag3Fe(CN)6. Phonon spectra have been measured using the inelastic neutron scattering technique as a function of temperature and…
We have carried out temperature-dependent x-ray diffraction and Raman scattering experiments on powder $Cs_3Bi_2Br_9$. Trigonal to monoclinic structural transition at around 95 K is discussed and shown to be driven by the softening of the…
Intriguing lattice dynamics has been predicted for aperiodic crystals that contain incommensurate substructures. Here we report inelastic neutron scattering measurements of phonon and magnon dispersions in Sr14Cu24O41, which contains…
The strongly correlated material FeSi exhibits several unusual thermal, magnetic, and structural properties under varying pressure-temperature (P-T) conditions. It is a potential thermoelectric alloy and a materials of several geological…
Single crystals of a ternary relaxor ferroelectric system, 0.29Pb(In1/2Nb1/2)O3-0.45Pb(Mg1/3Nb2/3)O3-0.26PbTiO3, have been studied using triple-axis based elastic and inelastic neutron scattering. Elastic diffuse scattering confirms the…
We report ultrafast quasiparticle (QP) dynamics and coherent acoustic phonons in undoped CaFe_2As_2 iron pnictide single crystals exhibiting spin-density wave (SDW) and concurrent structural phase transition at temperature TSDW ~ 165 K…
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$_2$…
The magnetic structure of BaFe2As2 was completely determined from polycrystalline neutron diffraction measurements soon after the ThCr2Si2-type FeAs-based superconductors were discovered. Both the moment direction and the in-plane…
Electronic structure near Fermi level of Pr2CoFeO6 (at 300 K) was investigated by X-ray photoemission spectroscopy (XPS) technique. All three cations, i.e., Pr, Co and Fe were found to be trivalent in nature. XPS analysis also suggested the…
Results of in-plane and out-of-plane thermal conductivity measurements on $\rm La_{1.8-x}Eu_{0.2}Sr_xCuO_4$ ($0\leq x\leq0.2$) single crystals are presented. The most characteristic features of the temperature dependence are a pronounced…
Time- and angle-resolved extreme ultraviolet photoemission spectroscopy is used to study the electronic structure dynamics in BaFe$_2$As$_2$ around the high-symmetry points $\Gamma$ and $M$. A global oscillation of the Fermi level at the…
Unlike covalent two-dimensional (2D) materials like graphene, 2D metals have non-layered structures due to their non-directional, metallic bonding. While experiments on 2D metals are still scarce and challenging, density-functional theory…
The diffusion of large databases collecting different kind of material properties from high-throughput density functional theory calculations has opened new paths in the study of materials science thanks to data mining and machine learning…
Diffraction Anomalous Fine Structure (DAFS) spectroscopy uses resonant elastic x-rays scattering as an atomic, shell and site selective probe that gives information on the electronic structure and the local atomic environment as well as on…