相关论文: Analysis of long range order
We show that in YVO3 new hard phonons gradually become zone center active below ~210 K verifying that a lattice phase transition takes place at about that temperature. The Debye-Waller factor found from EXAFS measurements show an additional…
We study the Holstein-Hubbard model at half filling to explore ordered phases including su- perconductivity (SC), antiferromagnetism (AF), and charge order (CO) in situations where the electron-electron and electron-phonon interactions are…
Positional polymorphism in solids refers to locally disordered unit cells that, on average, reproduce the high-symmetry structures observed in diffraction experiments. Standard theories of electron-phonon interactions fail to describe the…
Van der Waals hosts intercalated with transition metal (TM) ions exhibit a range of magnetic properties strongly influenced by the structural order of the intercalants. However, predictive computational models for the intercalant ordering…
We report Electron Paramagnetic Resonance measurements on single crystalline and powder samples of Nd_0.5Ca_0.5MnO_3 across the charge-ordering transition at T_co=240 K down to the antiferromagnetic ordering transition at T_N = 140 K. The…
Alloys with a first-order magnetic transition are central to solid-state refrigeration technology, sensors and actuators, or spintronic devices. The discontinuous nature of the transition in these materials is a consequence of the coupling…
The interplay of electron-electron and electron-phonon interactions is studied analytically in the Kondo regime. A Holstein electron-phonon coupling is shown to produce a weakening of the gate voltage dependence of the Kondo temperature and…
Common substitutional isovalent semiconductor alloys usually form disordered metastable phases with positive excess formation enthalpies ({\Delta}H). In contrast, monolayer alloys of transition metal dichalcogenides (TMDs) MX2 (M = Mo, W; X…
Thermal resonance, in which the temperature amplitude attains a maximum value (peak) in response to an external exciting frequency source, is a phenomenon pertinent to the presence of underdamped thermal oscillations and explicit…
Spin correlations in metallic and insulating phases of $V_2O_3$ and its derivatives are investigated using magnetic neutron scattering. Metallic samples have incommensurate spin correlations varying little with hole doping. Paramagnetic…
Combined effects of electron correlations and lattice distortions are investigated on the charge ordering in \theta-(BEDT-TTF)2RbZn(SCN)4 theoretically in a two-dimensional 3/4-filled extended Hubbard model with electron-lattice couplings.…
Using a variety of thermodynamic measurements made in magnetic fields, we show evidence that the diffusionless transition (DT) in many shape-memory alloys is related to significant changes in the electronic structure. We investigate three…
We theoretically investigate spin-dependent carrier dynamics due to the electron-phonon interaction after ultrafast optical excitation in ferromagnetic metals. We calculate the electron-phonon matrix elements including the spin-orbit…
Stacking fault energy dictates phase stability and deformation behavior in Co alloys and WC-Co cemented carbides, yet a quantitative assessment of alloying effects at finite temperatures remains poorly established. By integrating…
It has recently been observed that the weakly coupled plane wave matrix model has a density of states which grows exponentially at high energy. This implies that the model has a phase transition. The transition appears to be of first order.…
We theoretically study the heat flux between electrons and phonons in a thin metallic film embedded in a suspended dielectric slab (called a \textit{membrane}, in accordance with the established nomenclature), forming a layered structure.…
Anomalies in the temperature dependences of the recoil-free factor, f, and the average center shift, <CS>, measured by 57-Fe Mossbauer Spectroscopy, were observed for the first time in the archetype of the \sigma-phase alloys system, Fe-Cr.…
Lattice vibrations in materials induce perturbations on the electron dynamics in the form of long-range (dipole and quadrupole) and short-range (octopole and higher) potentials. The dipole Fr\"ohlich term can be included in current…
Atom scattering is becoming recognized as a sensitive probe of the electron-phonon interaction parameter $\lambda$ at metal and metal-overlayer surfaces. Here, the theory is developed linking $\lambda$ to the thermal attenuation of atom…
The Debye-Waller factor has been calculated for stabilized delta-phase plutonium with 5% aluminum. A quasi-harmonic Born-von Karman force model with temperature dependent phonon frequencies was used to calculate the mean-square thermal…