Related papers: MgO surface lattice phonons observation during Int…
The crystal lattice of Sr$_2$IrO$_4$ is investigated with synchrotron X-ray powder diffraction under hydrostatic pressures up to $P=43$ GPa and temperatures down to $20$ K. The tetragonal unit cell is maintained over the whole investigated…
The Mott insulator YVO$_{3}$ with $T_{N}$ = 118 K is revisited to explore the role of spin, lattice and orbital correlations across the multiple structural and magnetic transitions observed as a function of temperature. Upon cooling, the…
Depending on the volume fraction and interparticle interactions, colloidal suspensions can form different phases, ranging from fluids, crystals, and glasses to gels. For soft microgels that are made from thermoresponsive polymers, the…
The lattice properties at low temperatures of two samples of NdFeAsO1-xFx (x=0.05 and 0.25) have been examined in order to investigate possible structural phase transition that may occur in the optimally doped superconducting sample with…
Magnetic phase transitions have been explored in a superlattice formed by stacking monolayers of $\rm LaTiO_{3}$ and $\rm LaVO_{3}$ alternately, using ab-initio density functional theory (DFT) and Monte-Carlo (MC) simulations. DFT derived…
We present results from a detailed experimental investigation of LaFeAsO, the parent material in the series of "FeAs" based oxypnictide superconductors. Upon cooling this material undergoes a tetragonal-orthorhombic crystallographic phase…
Phonons, quantized vibrations of the atomic lattice, are fundamental to understanding thermal transport, structural stability, and phase behavior in crystalline solids. Despite advances in computational materials science, most predictions…
Polarized infrared reflectivity spectra of a (110)-oriented TbScO3 single crystal plate were measured down to 10 K. The number of observed polar phonons active along the crystallographic c axis at low temperatures is much higher than…
Higher-order phonon scatterings beyond fourth order remain largely unexplored despite their potential importance in strongly anharmonic materials at elevated temperatures. We develop a theoretical formalism for first-principles calculation…
(MgFe)O is a solid solution with ferrous iron undergoing the high to low spin state (HS-LS) crossover under high pressure. The exact state of the material in the region of the crossover is still a mystery, as domains with different spin…
First-order magnetostructural phase transitions underpin giant magnetocaloric effects, yet the microscopic role of lattice dynamics in these transitions remains controversial. Here we use first-principles spin-lattice dynamics simulations…
High-pressure experiments using diamond anvils have revealed novel properties and phase behavior of H2O under extreme conditions. When contained in diamond-anvil cells, the H2O samples are usually in direct contact with the diamond anvil.…
We combine a wide variety of experimental techniques to analyze two heretofore mysterious phase transitions in multiferroic bismuth ferrite at low temperature. Raman spectroscopy, resonant ultrasound spectroscopy, EPR, X-ray lattice…
The first-principles periodic linear combination of atomic orbitals method within the framework of density functional theory implemented in the CRYSTAL06 code has been applied to explore effect of pressure on the Compton profiles and…
Recent neutron diffraction and NMR studies suggest that the incommensurately modulated spin cycloid structure of BiFeO3 is stable down to 4.2 K, whereas DC [M(T)] and AC [\c{hi} ({\omega}, T)] magnetization, and caloric studies have…
Employing a first-principles and model Hamiltonian approach, we work out the electronic properties of polar-polar LaVO$_3$/KTaO$_3$ (LVO/KTO, 001) heterostrctures, with up to six layers of KTO and five layers of LVO. Our analyses indicate…
We have investigated the thermally induced proton/deuteron exchange in mixed amorphous H$_2$O:D$_2$O ices by monitoring the change in intensity of characteristic vibrational bending modes of H$_2$O, HDO, and D$_2$O with time and as function…
The origin of the lowest-temperature anomaly reported several years ago using a polycrystalline sample of the spin ice compound Dy2Ti2O7 had remained unresolved. Here we finally clarify its origin by susceptibility measurements down to 65…
Below the melting temperature $T_m$ crystals are the stable phase of typical elemental or molecular systems. However, cooling down a liquid below $T_m$, crystallization is anything but inevitable. The liquid can be supercooled, eventually…
Using ab initio molecular dynamics simulations, we calculate the physical properties of MgO at conditions extending from the ones encountered in the Earth mantle up to the ones anticipated in giant planet interiors such as Jupiter. We pay…