Metal-Insulator Transition and Orbital Order in PbRuO3 (2008)
Kimber, S. A. J., Rodgers, J. A., Wu, H., Murray, C. A., Argyriou, D. N., Fitch, A. N., ...
Anomalous low temperature electronic and structural behaviour has been discovered in PbRuO3. The structure (space group Pnma, a = 5.56314(1), b = 7.86468(1), c = 5.61430(1) A) and metallic...
Ising magnetism and ferroelectricity in Ca$_3$CoMnO$_6$ (2008)
Wu, Hua, Burnus, T., Hu, Z., Martin, C., Maignan, A., Cezar, J. C., ...
The origin of both the Ising chain magnetism and ferroelectricity in Ca$_3$CoMnO$_6$ is studied by $ab$ $initio$ electronic structure calculations and x-ray absorption spectroscopy. We find that...
Enhanced dimerization of TiOCl under pressure: spin-Peierls - to - Peierls transition (2008)
Blanco-Canosa, S., Rivadulla, F., Pineiro, A., Pardo, V., Baldomir, D., Khomskii, D. I., ...
We report high-pressure x-ray diffraction and magnetization measurements combined with ab-initio calculations to demonstrate that the high-pressure optical and transport transitions recently reported...
Doped orbitally-ordered systems: another case of phase separation (2008)
Kugel, K. I., Rakhmanov, A. L., Sboychakov, A. O., Khomskii, D. I.
A possible mechanism of electronic phase separation in the systems with orbital ordering is analyzed. We suggest a simple model taking into account an interplay between the delocalization of charge...
Homopolar bond formation in ZnV$_2$O$_4$ close to a metal-insulator transition (2008)
Pardo, V., Blanco-Canosa, S., Rivadulla, F., Khomskii, D. I., Baldomir, D., Wu, Hua, ...
Electronic structure calculations for spinel vanadate ZnV$_2$O$_4$ show that partial electronic delocalization in this system leads to structural instabilities. These are a consequence of the...
Spin-state polaron in lightly hole-doped LaCoO_3 (2008)
Podlesnyak, A., Russina, M., Furrer, A., Alfonsov, A., Vavilova, E., Kataev, V., ...
Inelastic neutron scattering (INS), electron spin (ESR) and nuclear magnetic resonance (NMR) measurements were employed to establish the origin of the strong magnetic signal in lightly hole-doped...
CaCrO3: an anomalous antiferromagnetic metallic oxide (2008)
Komarek, A. C., Streltsov, S. V., Isobe, M., Moeller, T., Hoelzel, M., Senyshyn, A., ...
Combining infrared reflectivity, transport, susceptibility and several diffraction techniques, we find compelling evidence that CaCrO3 is a rare case of a metallic and antiferromagnetic...
We discuss the ground state of the spin-orbital model for spin-one ions with partially filled $t_{2g}$ levels on a honeycomb lattice. We find that the orbital degrees of freedom induce a spontaneous...
Electronic orbital currents and polarization in Mott insulators (2008)
Bulaevskii, L.N., Batista, C.D., Mostovoy, M.V., Khomskii, D.I.
Strongly correlated electron insulators are one of the most important classes of materials in modern solid-state physics. We demonstrate that certain classes of Mott insulators, that usually are...
Streltsov, S. V., Khomskii, D. I.
The results of the LSDA+U calculations for pyroxenes with diverse magnetic properties (Li,Na)TM(Si,Ge)$_2$O$_6$, where TM is the transition metal ion (Ti,V,Cr,Mn,Fe), are presented. We show that the...
Effect of light Sr doping on the spin-state transition in LaCoO_3 (2006)
Podlesnyak, A., Conder, K., Pomjakushina, E., Mirmelstein, A., Allenspach, P., Khomskii, D. I.
We present an inelastic neutron scattering study of the low energy crystal-field excitations in the lightly doped cobalt perovskite La_0.998Sr_0.002CoO_3. In contrast to the parent compound LaCoO_3...
Possible spin-glass state in SmSr-manganites as the origin of the magnetization jumps (2006)
Kalinov, A.V., Fisher, L.M., Voloshin, I.F., Babushkina, N.A., Khomskii, D.I., Palstra, T.T.M.
Magnetic field-induced step-like changes in magnetization of Sm1-xSrxMnO3 manganites were studied. A strong dependence of these features on the magnetic-field sweep rate was observed. The notable...
Podlesnyak, A., Streule, S., Mesot, J., Medarde, M., Pomjakushina, E., Conder, K., ...
A gradual spin-state transition occurs in LaCoO3 around T~80-120 K, whose detailed nature remains controversial. We studied this transition by means of inelastic neutron scattering (INS), and found...
Pressure-induced insulating state in (La,Sr)CoO_{3} (2004)
Lengsdorf, R., Ait-Tahar, M., Saxema, S.S., Ellerby, M., Khomskii, D.I., Micklitz, H., ...
We have investigated the effect of pressure on the electronic, magnetic, and structural properties on a single crystal of conducting, ferromagnet (TC=157 K) La0.82Sr0.18CoO3 located near the boundary...
Orbital Ordering in Charge Transfer Insulators (2004)
Mostovoy, M.V., Khomskii, D.I.
We discuss a new mechanism of orbital ordering, which in charge transfer insulators is more important than the usual exchange interactions and which can make the very type of the ground state of a...
Transition from Mott Insulator to Superconductor in GaNb4Se8 and GaTa4Se8 under High Pressure (2004)
Abd-Elmeguid, M. M., Ni, B., Khomskii, D. I., Pocha, R., Johrendt, D., Wang, X., ...
Frustrated Spin Model as a Hard-Sphere Liquid (2003)
Mostovoy, M.V., Khomskii, D.I., Knoester, J., Prokof’ev, N.V.
We show that one-dimensional topological objects (kinks) are natural degrees of freedom for an antiferromagnetic Ising model on a triangular lattice. Its ground states and the coexistence of spin...
Orbital ordering and frustrations (2003)
Khomskii, D.I., Mostovoy, M.V.
Orbital ordering occurs in many transition metal compounds with Jahn–Teller ions (Cu2+, Mn3+, low-spin Ni3+, Ti3+ etc). It plays an important role in these materials. At the same time, exchange...
Frustrated Spin Model as a Hard-Sphere Liquid (2003)
Mostovoy, M.V., Khomskii, D.I., Knoester, J., Prokof’ev, N.V.
We show that one-dimensional topological objects (kinks) are natural degrees of freedom for an antiferromagnetic Ising model on a triangular lattice. Its ground states and the coexistence of spin...
Coupled spin-charge dynamics in NaV2O5 and its effect on the optical absorption (2002)
Mostovoy, M.V., Khomskii, D.I., Knoester, J.
We argue that in the quarter filled ladder compound NaV2O5 the quasi-one-dimensional spin system is strongly coupled to an antiferroelectric mode with a broad band. This mode is the single-electron...
Coupled spin-charge dynamics in NaV2O5 and its effect on the optical absorption (2002)
Mostovoy, M.V., Khomskii, D.I., Knoester, J.
We argue that in the quarter filled ladder compound NaV2O5 the quasi-one-dimensional spin system is strongly coupled to an antiferroelectric mode with a broad band. This mode is the single-electron...
Orbital Ordering in Frustrated Jahn-Teller Systems with 90° Exchange (2002)
Mostovoy, M.V., Khomskii, D.I.
We show that superexchange interactions in frustrated Jahn-Teller systems with transition metal ions connected by the 90° metal-oxygen-metal bonds (e.g., NaNiO2, LiNiO2, and ZnMn2O4) are much...
Pomjakushin, V. Y., Balagurov, A. M., Elzhov, T. V., Sheptyakov, D. V., Fischer, P., Khomskii, D. I., ...
Crystal and magnetic structures of complex manganese oxides Sr2GaMnO5+delta (deltasimilar or equal to0.01,0.52) and Ca2GaMnO5+delta (deltasimilar or equal to0.05) were studied by neutron powder...
Magnetic polarons in materials with colossal magnetoresistance (2000)
Kagan, M.Yu., Mostovoy, M.V., Khomskii, D.I.
We construct a phase diagram for the materials with colossal magnetoresistance. The basic model which describes these materials is a double-exchange model. We rigorously prove that a ground state of...
Dielectric anomaly in NaV2O5: evidence for charge ordering (2000)
Smirnov, A.I., Popova, M.N., Sushkov, A.B., Golubchik, S.A., Khomskii, D.I., Mostovoy, M.V., ...
We found a high-frequency dielectric and magnetic anomaly in NaV2O5 at the phase transition into the spin-gap state. The dielectric constant anomaly is of the antiferroelectric type, which is in...
Charge ordering and opening of spin gap in NaV2O5 (2000)
Mostovoy, M.V., Khomskii, D.I.
We argue that the origin of the phase transition in quasi-one-dimensional antiferromagnet NaV2O5 is not the spin-Peierls (SP) instability, but a charge ordering. The opening of the spin gap and the...
Double-exchange model: phase separation versus canted spins (1999)
Kagan, M.Yu., Khomskii, D.I., Mostovoy, M.V.
We study the competition between different possible ground states of the double-exchange model with strong ferromagnetic exchange interaction between itinerant electrons and local spins. Both for...
High-frequency dielectric and magnetic anomaly at the phase transition in NaV2O5 (1999)
Smirnov, A.I., Popova, M.N., Sushkov, A.B., Golubchik, S.A., Khomskii, D.I., Mostovoy, M.V., ...
We found anomalies in the temperature dependence of the dielectric and magnetic susceptibility of NaV2O5 in the microwave and far-infrared frequency ranges. The anomalies occur at the phase...