相关论文: Absence of orbital-selective Mott transition in Ca…
A new concept is proposed for the paramagnetic metal insulator transition in the layer perovskite Ca_{2-x}Sr_xRuO_4. Whereas the pure Sr compound is metallic up to very large Coulomb energies due to strong orbital fluctuations, structural…
Photoemission spectra of the perovskites Ca$_x$Sr$_{1-x}$VO$_3$, Ca$_x$La$_{1-x}$VO$_3$, and SrRuO$_3$ indicate that Coulomb correlations are more pronounced at the surface than in the bulk. To investigate this effect we use the dynamical…
The importance of electronic correlation effects in the layered perovskite Sr$_2$RuO$_4$ is evidenced. To this end we use state-of-the-art LDA+DMFT (Local Density Approximation + Dynamical Mean-Field Theory) in the basis of Wannier…
We investigated the electronic structures of the two-dimensional layered perovskite Sr$_{2}$\textit{M}O$_{4}$ (\textit{M}=4\textit{d} Ru, 4\textit{d} Rh, and 5\textit{d} Ir) using optical spectroscopy and polarization-dependent O…
We study the origin of the temperature-induced Mott transition in Ca2RuO4. As a method we use the local-density approximation+dynamical mean-field theory. We show the following. (i) The Mott transition is driven by the change in structure…
We investigated the electronic structures of the perovskite-type 4$d$ transition metal oxides Sr$M$O$_3$ ($M$ = Zr, Mo, Ru, and Rh) using their optical conductivity spectra $\sigma (\omega)$. The interband transitions in $\sigma (\omega)$…
We present first-principles studies on the orbital states of the layered perovskites Ca$_{2-x}$Sr$_x$RuO$_4$. The crossover from antiferromagnetic (AF) Mott insulator for $x < 0.2$ to nearly ferromagnetic (FM) metal at $x=0.5$ is…
We theoretically investigate magnetic properties of Sr$_2$TcO$_4$, a 4d transition-metal layered perovskite of the K$_2$NiF$_4$-type with half-filled t$_{2g}$ states. The effect of local Coulomb repulsion between the t$_{2g}$ orbitals is…
Dimensionality and electronic correlations are crucial elements of many quantum material properties. An example is the change of the electronic structure accompanied by the loss of quasiparticles when a metal is reduced from three…
We present evidence for quantum oscillations in the pressure-induced metallic state of the 4$d$ layered perovskite Ca$_2$RuO$_4$. A complicated oscillation spectrum is observed, which is both temperature and field dependent, with unusually…
Insulator-to-metal transition in Ca$_{2}$RuO$_{4}$ has drawn keen attention because of its sensitivity to various stimulation and its potential controllability. Here, we report a direct observation of Fermi surface, which emerges upon…
We propose a new mechanism for the paramagnetic metal-insulator transition in the layered perovskite Ca$_{2-x}$Sr$_{x}$RuO$_{4}$ (0<x<0.2). The LDA+U approach including spin-orbit coupling is used to calculate the electronic structures. In…
We investigate the Mott transitions in two-band Hubbard models with different bandwidths. Applying dynamical mean field theory, we discuss the stability of itinerant quasi-particle states in each band. We demonstrate that separate Mott…
We have investigated the electronic structure of Sr2IrO4 within the density-functional theory using the generalized gradient approximation while taking into account strong Coulomb correlations in the framework of the fully relativistic…
We report the complex dielectric function along and perpendicular to the IrO2 planes in the layered perovskite Sr2IrO4 determined by spectroscopic ellipsometry in the spectral range from 12 meV to 6 eV. Thin high quality single crystals…
The single-layered perovskite Ca$_2$RuO$_4$, characterized by a 4$d^4$ electron configuration, has been studied from first principles using density functional theory (DFT) using the generalized gradient approximation, with inclusion of…
A series of layered perovskites Sr$_2$$M$O$_4$ ($M$=Ti, V, Cr, and Mn) is studied by $ab $ $initio$ calculations within generalized gradient approximation (GGA) and GGA+$U$ schemes. The total energies in different magnetic configurations,…
Optical conductivity spectra of single crystals of Ca_1-xSr_xVO_3 have been studied to elucidate how the electronic behavior depends on the strength of the electron correlation without changing the nominal number of electrons per vanadium…
We investigate the nature and origin of the metal-insulator transition in Sr2Ru1-xTixO4 as a function of increasing Ti content (x). Employing detailed core, valence, and conduction band studies with x-ray and ultraviolet photoelectron…
The study of the strength of correlations in Na$_x$CoO$_2$ is extended to the x=0 end of the phase diagram where Mott insulating behavior has been widely anticipated. Inclusion of correlation as modeled by the LDA+U approach leads to a Mott…