The influence of the crystalline field on Kondo effect compounds with cerium is studied in framework an effective Hamiltonian which describes resonant scattering character and takes into account combined spin orbit exchange scattering. third-order perturbation-theory thermoelectric power computed exactly case two levels split by field. model applied to thermoelectric-power measurements ${\mathrm{Ce}}_{1\ensuremath{-}x}{\mathrm{La}}_{x}{\mathrm{Al}}_{3}$ agreement experiment good, especially...

We present a theoretical study of the magnetic polaron associated with an electron-hole pair in diluted semiconductor quantum dot. It is based on effective-mass approximation strong confinement regime, which incorporates coupling between light- and heavy-hole bands. The polaron, arising from sp-d exchange interaction confined carriers ions, treated self-consistent mean-field approach that leads to coupled nonlinear Schr\"odinger equations for electron hole. local response effective field...

We present a theoretical study of the effective exchange interaction arising from hybridization between valence-band states and localized d orbitals transition-metal impurity in II-VI semiconductor. The irreducible tensor method is used to deduce Hamiltonian manifold ground multiplet 3${\mathit{d}}^{\mathit{n}}$ ion tetrahedral crystal field. There no coupling cases ${\mathrm{Sc}}^{2+}$ ${\mathrm{Ti}}^{2+}$ ions. For ${\mathrm{Mn}}^{2+}$, ${\mathrm{Fe}}^{2+}$, ${\mathrm{Co}}^{2+}$ reduces...

We present a theoretical study of the optical properties quantum dots containing single paramagnetic ion. The eigenvalue problem an electron-hole pair in interaction with localized spin is solved. In Mn-doped nanocrystals II-VI semiconductors such as CdTe fundamental absorption line splits into six components, whose relative intensities strongly depend on Mn orientation respect to polarization light, suggesting possibility detection spin. With atom at center dot overall zero-field splitting...

Experimental data of donor-acceptor--pair time-resolved spectroscopy in ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Mn}}_{\mathrm{x}}$Te alloys are used to extract the acceptor binding energy as a function temperature and composition. This is done between 1.6 35 K, for compositions x\ensuremath{\le}0.1. The magnetic part this explained terms bound-magnetic-polaron formation. We present statistical-mechanical theory that goes beyond Gaussian approximation. It also takes into...

The low-temperature resistivity and magnetoresistivity of cerium compounds are computed with a model describing both the crystalline field Kondo effects, thus extending to low temperatures previous calculation [Phys. Rev. B 5, 4541 (1972)]. theoretical results can account for data compounds, either those which order magnetically (such as ${\mathrm{CeAl}}_{2}$ or ${\mathrm{CeB}}_{6}$) become nonmagnetic ${\mathrm{CeAl}}_{3}$ ${\mathrm{CeCu}}_{2}$${\mathrm{Si}}_{2}$) at temperatures.

In order to understand the low temperature anomalous properties of some rare-earth compounds (such as CeAl2, CeAl3, TmSe), we introduce a Kondo lattice hamiltonian in which localized 1/2 spin per site interacts antiferromagnetically with conduction electron spins. We investigate ground state this by using real space renormalization group method. After studying simpler one dimensional analog study original dimension when there is site.

We investigate here the strain-induced growth of Cu at 600 °C and its interactions with a thermally grown, 270 nm-thick SiO2 layer on Si(111) substrate. Our results show clear evidence triangular voids formation islands surface via void-filling mechanism upon deposition, even dielectric. Different coordination states, oxidation numbers, chemical compositions Cu-grown film are estimated from core level X-ray photoelectron spectroscopy (XPS) measurements. find different compound phases...

The photoluminescence spectra of spherical CdTe nanocrystals with zincblende structure are studied by size-selective spectroscopic techniques. We observe a resonant Stokes shift 15 meV when the excitation laser energy is tuned to red side absorption band at 2.236 eV. experimental data analyzed within symmetry-based tight-binding theory exciton spectrum, which first shown account for size dependence fundamental gap reported previously in literature. theoretical presented as function shows...

Abstract The interaction between graphene and silver nanoparticles (AgNPs) is investigated by studying the surface-enhanced Raman spectroscopy (SERS) that shows a large enhancement of signal from AgNPs coated compared to bare graphene. In addition, electrical nature sample examined using two-probe probe station acquire current-voltage (I-V) characteristics exhibiting semi-conducting current behaviour AgNPs-graphene heterojunctions, in contrast semi-metallic electronic observed for pristine...

We present a simple model for the magnetic polaron associated with an electron-hole pair in semimagnetic semiconductor quantum dot. An exactly soluble Hamiltonian based on effective-mass approximation is used to calculate equilibrium properties. The binding energy decreases increasing temperature or field. Low-temperature magnetization and luminescence polarization show rapid saturation Strong light-induced enhancement of predicted.

We present a theoretical study of the effect reduced dimensionality on Zeeman splittings electron and hole states. It is based effective mass approximation for confined states wave vector dependence $\mathrm{sp}\ensuremath{-}d$ exchange interaction parameters in bulk semimagnetic semiconductor. find that ratio exciton splitting to magnetization nanostructure with respect by factor $\ensuremath{\rho}$ depends degree confinement. The relatively small (a few percent) quantum wells, but as...

The third-order perturbation-theory thermal conductivity is computed in the framework of effective exchange Hamiltonian which describes both resonant-scattering character and crystalline field effect cerium. model applied to measurements cerium compounds good agreement found for ${\mathrm{CeAl}}_{2}$ ${\mathrm{CeCu}}_{2}$${\mathrm{Si}}_{2}$.

The optical spectra of CdSe nanocrystals up to 55 \AA{} in diameter are analyzed a wide range energies from the fine structure low-energy excitations so-called high-energy transitions. We apply symmetry-based method two steps. First we take tight-binding (TB) parameters bulk ${\mathrm{sp}}^{3}{s}^{*}$ TB model, extended include spin-orbit interaction. full single-particle obtained an exact diagonalization by using group-theoretical treatment. electron-hole interaction is next introduced:...

A group-theoretical analysis is used to express the Zeeman splittings of interband optical transitions at a critical point \ensuremath{\Lambda} or L in terms band-electron--Mn-d-electron exchange interaction values that k. The ${\mathrm{\ensuremath{\sigma}}}_{+}$-to-${\mathrm{\ensuremath{\sigma}}}_{\mathrm{\ensuremath{-}}}$ overall splitting ${\mathit{E}}_{1}$ transition...

Coplanar heterojunctions composed of van der Waals layered materials with different structural polymorphs have drawn immense interest recently due to low contact resistance and high carrier injection rate owing Schottky barrier height. Present research has largely focused on efficient exfoliation these their restacking achieve better performances. We present here a microwave assisted easy, fast route induce concentration metallic 1T phase in the original 2H matrix exfoliated MoS2 layers thus...

Measurements of the electrical resistivity, thermoelectric power and thermal conductivity from 1.5 to 300 K in single crystal CePt 2 Si are reported here. A theoretical model, based on effective exchange Hamiltonian taking into account anisotropy conduction electron relaxation time, is also presented explain strong observed transport properties cerium Kondo compound Nous presentons ici des mesures de la resistivite electrique, du pouvoir thermoelectrique et conductivite thermique d'un...

X-ray standing wave fields, excited in periodic nanostructured multilayers during Bragg diffraction, have been used to probe atomic migration multilayers. Ion beam induced of Fe impurity atoms from the C layers Pt a Pt(Fe)/C(Fe) multilayer, where each layer is about 2 nm thick, has detected. With depth resolution better than 0.2 this technique, direction (here outward) and change concentration (also Pt) determined. The results such measurements are important for understanding properties...