Related papers: Phonons reflect dynamic spin-state order in LaCoO$…
Following previous works reporting an anomalous behavior of several zone-center optical phonons across the magnetic transition of square lattice iridates Sr2IrO4 and Sr3Ir2O7, we have investigated the lattice dynamics as a function of…
We report on an extended fluctuation regime in the spin dimer system Sr3Cr2O8 based on anomalies in Raman active phonons and magnetic scattering. The compound has two characteristic temperatures, TS = 275 K, related to a Jahn-Teller…
LaCoO$_3$ provides a poignant example of a transition metal oxide where the cobalt cations display multiple spin states and spin transitions and which continues to garner substantial attention. In this work, we describe first principles…
We have studied ultrafast dynamics of thin films of LaCoO$_3$ and La$_{0.5}$Sr$_{0.5}$CoO$_3$ with femtosecond pump-probe ellipsometry in the energy range of 1.6-3.4 eV. We have observed a large pump-induced transfer of spectral weight in…
We study squeezed quantum states of phonons, which allow the possibility of modulating the quantum fluctuations of atomic displacements below the zero-point quantum noise level of coherent phonon states. We calculate the corresponding…
Copper borate Cu$_3$(BO$_3$)$_2$ is a complex compound with a layered crystallographic structure in which the Jahn-Teller active and magnetic copper Cu$^{2+}$ ions occupy sixteen nonequivalent positions in the unit cell displaying…
We report ^{31}P and ^{139}La NMR studies of (La_{0.87}Ca_{0.13})FePO, which is a family member of the recently discovered superconductor LaFeAs(O_{1-x}F_x). In the normal state, Knight shift and $1/T_1T$ show that a Fermi-liquid state with…
We investigate the crystal structure and lattice vibrations of Sr$_2$IrO$_4$ by a combined phonon Raman scattering and x-ray powder diffraction experiment under pressures up to $66$ GPa and room temperature. Density functional theory (DFT)…
Synthetic powder, ore samples and mineral single crystals of goethite ($\alpha-$FeOOH) were investigated with polarized Raman spectroscopy at temperatures from 300 K to 473 K. The symmetry of the vibrational modes, observed in different…
In this work we present the results of an inelastic x-ray scattering experiment detailing the behavior of the transverse acoustic [110] phonon in BaFe2As2 as a function of temperature. When cooling through the structural transition…
Neutron scattering and ultrasonic methods have been used to study the lattice dynamics of two single crystals of Ni-Mn-In Heusler alloys close to Ni$_{50}$Mn$_{34}$In$_{16}$ magnetic superelastic composition. The paper reports the…
In the scientific description of unconventional transport properties of oxides (spin-dependent transport, superconductivity etc.), the spin-state degree of freedom plays a fundamental role. Because of this, temperature- or magnetic…
The variational cluster approximation is applied to the calculation of thermodynamical quantities and single-particle spectra of LaCoO3. Trial self-energies and the numerical value of the Luttinger-Ward functional are obtained by exact…
To gain control over magnetic order on ultrafast time scales, a fundamental understanding of the way electron spins interact with the surrounding crystal lattice is required. However, measurement and analysis even of basic collective…
We present a neutron scattering study of stripe correlations measured on a single crystal of La$_{1.875}$Ba$_{0.125}$CuO$_{4}$. Within the low-temperature-tetragonal (LTT) phase, superlattice peaks indicative of spin and charge stripe order…
We have investigated the effect of pressure on the electronic, magnetic, and structural properties on a single crystal of conducting, ferromagnet (T$_{C}$=157K) La$_{0.82}$Sr$_{0.18}$CoO$_{3}$ located near the boundary of the…
The mechanism responsible for the extraordinary interface conductivity of LaAlO$_{3}$ on SrTiO$_{3}$ and its insulator-metal transition remains controversial. Here, using density functional theory calculations, we establish a comprehensive…
We report ultrasound studies of spin-lattice and single-ion effects in the spin-ice materials Dy$_2$Ti$_2$O$_7$ (DTO) and Ho$_2$Ti$_2$O$_7$ (HTO) across a broad field range up to 60 T, covering phase transformations, interactions with…
Rare-earth orthoferrites are a promising platform for antiferromagnetic spintronics with a rich variety of terahertz spin and lattice dynamics phenomena. For instance, it has been experimentally demonstrated that the light-driven optical…
We report inelastic neutron scattering measurements of the phonon density-of-states in superconducting Sr0.6K0.4Fe2As2 (Tc=30 K) and Ca0.6Na0.4Fe2As2 (Tc=18 K). Compared with the parent compound BaFe2As2 doping affects mainly the lower and…