Papers by gabriel kotliar
Physica C: Superconductivity, 1991
ganter.chemie.uni-dortmund.de
We report on the formation of tetrahydrofuran clathrate hydrate studied by x-ray Raman scattering... more We report on the formation of tetrahydrofuran clathrate hydrate studied by x-ray Raman scattering measurements at the oxygen K-edge. A comparison of x-ray Raman spectra measured from water/tetrahydrofuran mixtures and tetrahydrofuran hydrate at different ...
EPL (Europhysics Letters), 2012
Reviews of Modern Physics, 1996
Physical Review Letters, 1995
Physical Review Letters, 2013
We propose a mechanism for binding of diatomic ligands to heme based on a dynamical orbital selec... more We propose a mechanism for binding of diatomic ligands to heme based on a dynamical orbital selection process. This scenario may be described as bonding determined by local valence fluctuations. We support this model using linear-scaling first-principles calculations, in combination with dynamical mean-field theory, applied to heme, the kernel of the hemoglobin metalloprotein central to human respiration. We find that variations in Hund's exchange coupling induce a reduction of the iron 3d density, with a concomitant increase of valence fluctuations. We discuss the comparison between our computed optical absorption spectra and experimental data, our picture accounting for the observation of optical transitions in the infrared regime, and how the Hund's coupling reduces, by a factor of five, the strong imbalance in the binding energies of heme with CO and O2 ligands. arXiv:1206.0412v2 [cond-mat.str-el]
Physical Review Letters, 2001
Physical Review Letters, 2012
We study the steady-state dynamics of the Hubbard model driven out-of-equilibrium by a constant e... more We study the steady-state dynamics of the Hubbard model driven out-of-equilibrium by a constant electric field and coupled to a dissipative heat bath. For very strong field, we find a dimensional reduction: the system behaves as an equilibrium Hubbard model in lower dimensions. We derive steady-state equations for the dynamical mean-field theory in the presence of dissipation. We discuss how the electric field induced dimensional crossover affects the momentum resolved and integrated spectral functions, the energy distribution function, as well as the steady current in the non-linear regime.
Physical Review Letters, 2012
Vanadium dioxide undergoes a first order metal-insulator transition at 340 K. In this work, we de... more Vanadium dioxide undergoes a first order metal-insulator transition at 340 K. In this work, we develop and carry out state of the art linear scaling DFT calculations refined with non-local dynamical mean-field theory. We identify a complex mechanism, a Peierls-assisted orbital selection Mott instability, which is responsible for the insulating M1 phase, and furthermore survives a moderate degree of disorder.
We use the Local Density Approximation in combination with the Dynamical Mean Field Theory to inv... more We use the Local Density Approximation in combination with the Dynamical Mean Field Theory to investigate intermediate energy properties of the copper oxides. We identify coherent and incoherent spectral features that results from doping a charge transfer insulator, namely quasiparticles, Zhang-Rice singlet band, and the upper and lower Hubbard bands. Angle resolving these features, we identify a waterfall like feature, between the quasiparticle part and the incoherent part of the Zhang-Rice band. We investigate the assymetry between particle and hole doping. On the hole doped side, there is a very rapid transfer of spectral weight upon doping in the one particle spectra. The optical spectral weight increases superlinearly on the hole doped side in agreement with experiments.
Physical Review B, 2010
Strong correlations effects, which are often associated to the approach to a Mott insulating stat... more Strong correlations effects, which are often associated to the approach to a Mott insulating state, in some cases may be observed even far from half-filling. This typically happens whenever the inter-site Coulomb repulsion induces a tendency towards charge ordering, an effect that confines the electrons, and in turn favors local moment formation, i.e. Mott localization. A distinct intermediate regime then emerges as a precursor of such a Wigner-Mott transition, which is characterized by both charge and spin correlations, displaying large mass enhancements and strong renormalizations of other Fermi liquid parameters. Here we present a careful study of a quarter filled extended Hubbard model -a simple example where such physics can be studied in detail, and discuss its relevance for the understanding of the phenomenology of low-density two dimensional electron gases.
We use the Local Density Approximation in combination with the Dynamical Mean Field Theory to car... more We use the Local Density Approximation in combination with the Dynamical Mean Field Theory to carry out a comparative investigation of a typical electron doped and a typical hole doped copper oxide, NCCO and LSCO respectively. The parent compounds of both materials are strongly correlated electron systems in the vicinity of the metal to charge transfer insulator transition. In NCCO the magnetic long range order is essential to open a charge transfer gap, while Mott physics is responsible for the gap in LSCO. We highlights the role of the apical oxygens in determining the strength of the correlations and obtaining overall good agreement between theory and several experimentally determined quantities. Results for optical conductivity, polarized X-ray absorption and angle resolved photoemission are presented and compared with experiments. arXiv:1005.3100v1 [cond-mat.str-el]
Physical Review B, 2011
We derive a general formalism for evaluating the high-frequency limit of the thermoelectric power... more We derive a general formalism for evaluating the high-frequency limit of the thermoelectric power of strongly correlated materials, which can be straightforwardly implemented in available first principles LDA+DMFT programs. We explore this formalism using model Hamiltonians and we investigate the validity of approximating the static thermoelectric power S 0 , by its hightemperature limit, S * . We point out that the behaviors of S * and S 0 are qualitatively different for a correlated Fermi liquid near the Mott transition, when the temperature is in the coherent regime.
Physica C: Superconductivity, 1991
The three band Hubbard modal with nearest neighbour repulsion is studied in the U = c~ limit usin... more The three band Hubbard modal with nearest neighbour repulsion is studied in the U = c~ limit using the slave boson technique and the large N expansion. A charge transfer (CT) instability is found like ill weak coupling theory. The CT instability is always associated with a divergin 8 compressibility leading to a phase separation. The total density and CT susceptibilities are analysed in both the static and dynamic lindt to gain insight on the strong mixing between the density fluctuations and the excitonic modes. The evaluation to order ~ of the effective scattering amplitude in the Cooper channel shows the presence of superconducting instabilities in the s and d wave channel near the phase separation.
High temperature superconductivity was achieved by introducing holes in a parent compound consist... more High temperature superconductivity was achieved by introducing holes in a parent compound consisting of copper oxide layers separated by spacer layers. Realizations of this phenomena has been achieved in multiple crystal structures and has been the subject of numerous investigations and extensive controversy. In a small number of copper oxide based materials, it is possible to dope the parent compound with electrons [1-3] , and their physical properties are bearing some similarities but also significant differences from the hole doped counterparts. For example, in the electron doped materials the antiferromagnetic phase is much more robust than the superconducting phase, while the normal state has a resistivity with a quadratic temperature dependence which is expected in normal metals rather than the linear temperature dependence observed in the hole doped systems. Here, we use a recently developed first principles method, to study the electron doped cuprates and elucidate the deep physical reasons why their behavior is so different than the hole doped materials. The crystal structure of the electron doped materials, characterized by a lack of oxygen in the apical position, results in a parent compound which is a Slater insulator. Namely, a material where the insulating behavior is the result of the presence of magnetic long range order. This is in sharp contrast with the hole doped materials, where the parent compound is a Mott charge transfer insulator, namely a material which is insulating due to the strong electronic correlations but not the magnetic order. We study the evolution of the angle resolved photoemission spectra and the optical properties of the normal state of the electron doped cuprates as a function of doping, clarifying how their unique position close to, but below the metal to charge transfer insulator transition, accounts for their surprising differences from the hole doped cuprates.
Journal of Physics: Condensed Matter, 1996
Journal of Magnetism and Magnetic Materials, 2007
We report on the formation of tetrahydrofuran clathrate hydrate studied by x-ray Raman scattering... more We report on the formation of tetrahydrofuran clathrate hydrate studied by x-ray Raman scattering measurements at the oxygen K-edge. A comparison of x-ray Raman spectra measured from water/tetrahydrofuran mixtures and tetrahydrofuran hydrate at different ...
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Papers by gabriel kotliar