A5044772380- Physics of Superconductivity and Magnetism
- Organic and Molecular Conductors Research
- Advanced Condensed Matter Physics
- Rare-earth and actinide compounds
- Molecular Junctions and Nanostructures
- 2D Materials and Applications
- Iron-based superconductors research
- High-pressure geophysics and materials
- Metallurgical and Alloy Processes
- Inorganic Chemistry and Materials
- Magnetic and transport properties of perovskites and related materials
- Quasicrystal Structures and Properties
- Organic Electronics and Photovoltaics
- Quantum and electron transport phenomena
- Thermodynamic and Structural Properties of Metals and Alloys
- Chalcogenide Semiconductor Thin Films
- Advanced Chemical Physics Studies
- Semiconductor materials and devices
- Electronic and Structural Properties of Oxides
- Conducting polymers and applications
- Solid-state spectroscopy and crystallography
- Perovskite Materials and Applications
- Theoretical and Computational Physics
- Semiconductor materials and interfaces
- X-ray Diffraction in Crystallography
University of Zagreb
2006-2025
University of Ljubljana
1999
Institute of Physics
1979-1998
Los Alamos National Laboratory
1989-1995
University of Cambridge
1994
The axial oxygen contributions to the Cu K-edge, polarized, extended x-ray-absorption fine structure of ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$ are analyzed from 10\ensuremath{\le}T\ensuremath{\le}105 K, using a novel approach in which radial distribution function is directly calculated model potentials. best fit obtained with double-well potential two nearly equally populated O(4) sites 0.13 \AA{} apart. site separation decreases 0.02 region near...
We describe a variational method to solve the Holstein model for an electron coupled dynamical, quantum phonons on infinite lattice. The space can be systematically expanded achieve high accuracy with modest computational resources (12-digit one-dimensional polaron energy at intermediate coupling). compute ground-state and low-lying excited-state properties of continuous values wave vector k in essentially all parameter regimes. Our results band, effective mass, correlation functions compare...
We consider a 3/4-filled, two-band discrete tight-binding Peierls-Hubbard model for an isolated chain of halogen-bridged, mixed-valence, transition-metal linear-chain complex (HMMC or MX chain). have employed the adiabatic approximation in which quantum fluctuations associated with phonons are implicitly treated as external field electrons, and treat electron-electron effects Hartree-Fock approximation. investigate ground states functions parameters doping-induced photoinduced...
We present exact diagonalization results of an electron-phonon model Hamiltonian for the O(4)-Cu(1)-O(4) cluster in ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$. For large enough electron--infrared-phonon coupling motion holes and ions becomes strongly correlated, i.e., polaronic, leading to a double-well structure infrared mode, as encountered x-ray-absorption fine structure. In contrast, associated Raman mode shows single-well behavior even electron--Raman-phonon coupling. The...
Analysis of polarized copper K-edge extended x-ray-absorption fine-structure (EXAFS) measurements on ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$ for temperatures 10\ensuremath{\le}${\mathit{T}}_{\mathrm{nom}}$\ensuremath{\le}105 K indicates that the axial oxygen moves in a double-well potential which softens within fluctuation region associated with onset superconductivity this material. This follows from coupling between phonons derived and superconducting order parameter. The...
A simple electron-phonon coupling model is constructed for the layered-metal oxides. The predictions of are tetragonal-to-orthorhombic instability and separately from it, bond dimerization within layers. High Tc in those materials associated with soft shear phonon branch their tetragonal state.
2014 Le transport collectif par les ondes de densité charge (CDW) se transforme en un courant ordinaire dans contacts avec le métal normal.Dans notre étude ce processus produit glissement phase (PS) CDW.Le CDW système quasi unidimensionnel une surface Fermi à « nesting » et présence d'impuretés est décrit équation différentielle non linéaire obtenue auparavant.Nous résolvons cette équa- tion numériquement pour des échantillons semi-infinis finis.L'analyse solutions faite champs électriques E...
We present a three-dimensional multiparticle Monte Carlo (3DMPMC) simulation of hopping transport in disordered organic molecular media. used this approach order to study the charge across an energetically heterojunction which is known strongly influence characteristics multilayer devices based on thin films. The role energetic disorder and its spatial correlations, govern bulk, are examined here for bilayer homopolar system where represents bottleneck transport. effects both sides...
Abstract Murunskite (K 2 FeCu 3 S 4 ) bridges the two known families of high‐temperature superconductors, cuprates and iron‐pnictides, structurally electronically. Like these families, murunskite exhibits an antiferromagnetic (AF)‐like response with ordered phase below 97 K. The magnetic iron atoms are randomly distributed over one‐quarter sites in two‐dimensional planes, while remaining occupied by non‐magnetic copper, evoking notion a high‐entropy alloy. This intriguing transition is...
We present a three-level model that addresses the possibility charge-transfer fluctuations are responsible for anomalously large intensity of 155 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ Ba mode observed by Genzel et al. The also accompanying Raman signature and c-axis lattice constant variations with oxygen content.
Abstract Thermal conductivity ( κ ) plays an essential role in functional devices. It is advantageous to design materials where one can tune a wide range according its function: single-crystals and nanowires of anatase polymorph titanium dioxide, broadly used applications ranging from photovoltaics, reflective coatings memristors, have been synthesized large quantities. Here we identify new, strong diffusion mechanism heat by polaronic structures due oxygen vacancies, which considerably...
Cu-O radial distribution functions in ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$, ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{6.5}$, and ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{2.8}$${\mathrm{Co}}_{0.2}$${\mathrm{O}}_{7+\mathrm{\ensuremath{\delta}}}$ at 10 K have been determined from Cu K-edge polarized extended x-ray-absorption fine structure of these materials, using model potentials to describe the effect relative motion. The analysis shows that axial oxygen atom...
Layered transition metal dichalcogenides (TMDs) are commonly classified as quasi-two-dimensional materials, meaning that their electronic structure closely resembles of an individual layer, which results in resistivity anisotropies reaching thousands. Here, we show this rule does not hold for 1T-TaS2 - a compound with the richest phase diagram among TMDs. While onset charge density wave order makes in-plane conduction non-metallic, reveal out-of-plane transport is metallic and anisotropy...
${\mathrm{Co}}_{1/3}{\mathrm{NbS}}_{2}$ is the magnetic intercalate of 2H-${\mathrm{NbS}}_{2}$ where electronic itinerant and properties strongly influence each other throughout phase diagram. Here we report angle-resolved photoelectron spectroscopy (ARPES) study in ${\mathrm{Co}}_{1/3}{\mathrm{NbS}}_{2}$. In agreement with previous reports, observed structure seemingly resembles one parent material 2H-${\mathrm{NbS}}_{2}$, shift Fermi energy 0.5 eV accounting for charge transfer...
We consider charge injection from a metal into amorphous organic molecular media with correlated disorder. It is shown that correlations, known to be essential for understanding the field dependence of carrier mobility, also strongly influence current distribution. In particular, we find hot spots are intrinsic metal/organic interfaces, even perfectly flat surfaces. The density variations reach several orders magnitude realistic material parameters. further induce channels in bulk extend...
The infrared absorption of the 155-${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ c-axis mode ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$ is calculated on basis an anharmonic-electron-phonon-interaction model and a large enhancement its intensity obtained. A double-well potential in electron-phonon interaction gives right order magnitude for shifts bridging O(4) position agreement with recent x-ray-absorption fine-structure data. Electron-density--two-phonon--interaction terms are...
We have developed a method based on real-space random-phase approximation (RPA) to study the phonon spectra of doped and undoped halogen-bridged transition-metal-chain complexes. The is very convenient in cases spatially inhomogeneous mean-field structures. Thus, we are able find usual extended modes as well local associated with polaron, bipolaron, kink, exciton, or impurity structures intrinsically extrinsically systems. corresponding infrared absorption Raman (as function excitation...
The possibility of long-period (``superlattice'') ground states is systematically investigated in a commensurate (3/4-filled), one-dimensional two-band Peierls-Hubbard Hamiltonian. This model has been proposed to describe halogen-bridged mixed-valence linear-chain compounds and analog Hamiltonian cuprate bismuthate oxide superconductors. Conventional superlattice phases are driven by competing length scales (for example, from incommensurate filling or an external potential). However, these...
Transition-metal dichalcogenides (TMDs) are layered compounds that support many electronic phases, including various charge density waves, superconducting, and Mott insulating states. Their intercalation with magnetic ions introduces sublayers, which strongly influence the coupling between host layers, feature states adjustable by external means. ${\mathrm{Co}}_{1/3}\mathrm{Nb}{\mathrm{S}}_{2}$ hosts a particularly sensitive subsystem lowest ordering temperature in family of magnetically...
The main contribution to the electron-phonon coupling in ionic metals with strongly correlated electrons is attributed deformation-induced variation of crystal field on those sites which are involved conduction. In layered-metal oxides latter assumed be oxygen CuO2 planes. holes a representative deformation mode lanthanum compounds evaluated using point charge approximation and Ewald method. Particular attention devoted orthorhombic-to-tetragonal instability formation corresponding polarons...
We have investigated anisotropic physical properties (the magnetic susceptibility, the electrical resistivity, thermoelectric power, Hall coefficient and thermal conductivity) of single-crystalline Taylor-phase ${\text{T}\text{-Al}}_{72.5}{\text{Mn}}_{21.5}{\text{Fe}}_{6.0}$ complex intermetallic that is an orthorhombic approximant to $d\text{-Al-Mn-Pd}$ decagonal quasicrystal. The measurements were performed along $a$, $b$, $c$ directions unit cell, where $(a,c)$ atomic planes are stacked...
The controversy regarding the precise nature of high-temperature phase $1T\text{\ensuremath{-}}\mathrm{TiS}{\mathrm{e}}_{2}$ lasts for decades. It has intensified in recent times when new evidence excitonic origin low-temperature charge-density wave state started to unveil. Here we address problem through measurements and detailed analysis optical response single crystals. separate responses electron hole subsystems are identified followed temperature. We show that neither semiconductor nor...
All the linear excitations are calculated in random-phase approximation around a doped inhomogeneous Hartree-Fock state as well undoped uniform antiferromagnetic one-dimensional Hubbard model. Upon doping, shape modes appear, localized an introduced hole, some ``shake-off'' branches related to combinations of local and extended orbitals. These addition spin wave ultragap pure state. Some characteristics similar bare processes t-t'-J model derived from at strong coupling. Spectral weights...
Halogen-bridged transition-metal chain compounds have recently emerged as an important class of low-dimensional electronic materials with strong electron-lattice and electron-electron interactions. We introduce a many-body model for such which is quantitatively successful highly valence-localized (strong charge-density-wave) members the class, e.g., PtCl various ligand structures. The introduces nearest-neighbor Coulomb attraction metal ion-ion electrostatic repulsion directly rather than...
It is shown that symmetric and antisymmetric (340 cm −1 ) Raman modes are strongly coupled respectively to the intracell, intraplanar oxygen-copper oxygen-oxygen charge fluctuations in YBa 2 Cu 3 O 7 . The dominant coupling arises from variations of crystal field with deformations. anomalous behavior 340 mode thus attributed corresponding in-plane correlation function. continuous at T c , this contrast examined within existing theories. appears Emery model a suitable starting point for...