Related papers: Jahn-Teller driven quadrupolar ordering and spin-o…
Exotic quantum phases, arising from a complex interplay of charge, spin, lattice and orbital degrees of freedom, are of immense interest to a wide research community. A well-known example of such an entangled behavior is the Jahn-Teller…
Vanadium spinels (ZnV_2O_4, MgV_2O_4, and CdV_2O_4) exhibit a sequence of structural and magnetic phase transitions, reflecting the interplay of lattice, orbital, and spin degrees of freedom. We offer a theoretical model taking into account…
We develop a microscopic theory of multipole interactions and orderings in 5$d^2$ transition metal ion compounds. In a cubic environment, the ground state of 5$d^2$ ions is a non-Kramers $E_g$ doublet, which is nonmagnetic but hosts…
The Ge-doped GaNb4Se8 polycrystalline samples were synthesized by solid-state reaction method. Zero resistance transitions were observed in one batch of samples with the highest onset superconducting Tc at 45 K. This discovery may…
The dynamic orientational order-disorder transition of clusters consisting of octahedral molecules is formulated in terms of symmetry-adapted rotator functions. The transition from a higher-temperature body-centered-cubic, orientationally…
We have re-investigated the crystal structure of a spinel type CuIr2S4 at low temperatures using a single-crystal in a synchrotron radiation x-ray diffraction experiment. The crystal structure of the low-temperature phase of CuIr2S4 has…
Structure with orbital degeneracy is unstable toward spontaneous distortion. Such orbital correlation usually has a much higher energy scale than spins, and therefore, magnetic transition takes place at a much lower temperature, almost…
Structural properties of CuAl$_{2}$O$_{4}$, which was recently argued to show unusual suppression of the Jahn-Teller distortions by the spin-orbit coupling, are investigated under pressures up to 6 GPa. Analysis of X-ray powder diffraction…
Using single crystal inelastic neutron scattering with and without application of an external magnetic field and powder neutron diffraction, we have characterized magnetic interactions in Ba$_3$Cr$_2$O$_8$. Even without field, we found that…
Temperature-dependent x-ray diffraction of the low-dimensional spin 1/2 quantum magnet TiOBr shows that the phase transition at T_{c2} = 47.1 (4) K corresponds to the development of an incommensurate superstructure. Below T_{c1} = 26.8 \pm…
We demonstrate that magnetic $3d$ impurities with $S=3/2$ spins and no orbital degree of freedom induce changes of spin-orbital order in a $4d^4$ Mott insulator with $S=1$ spins. Impurities act either as spin defects which decouple from the…
Neutron inelastic scattering and diffraction techniques have been used to study the MnV2O4 spinel system. Our measurements show the existence of two transitions to long-range ordered ferrimagnetic states; the first collinear and the second…
We study the phase transition between the high temperature algebraic liquid phase and the low temperature ordered phase in several different types of locally constrained O(N) spin systems, using a unified constrained Ginzburg-Landau…
The Jahn-Teller theorem constitutes one of the most popular and stringent concepts, applicable to all fields of chemistry. In open shell transition elements chemistry and physics, 3d4, 3d9, and 3d7(low-spin) configurations in octahedral…
We present a thorough analysis of the interplay of magnetic moment and the Jahn-Teller effect in the $\Gamma_8$ cubic multiplet. We find that in the presence of dynamical Jahn-Teller effect, the Zeeman interaction remains isotropic, whereas…
Cubic spinel GeNi2O4 exhibits intriguing magnetic properties with two successive antiferromagnetic phase transitions (TN1 12.1 and TN2 11.4 K) with the absence of any structural transition. We have performed detailed heat capacity and…
Orbitally degenerate systems provide a promising platform for realizing novel quantum phases driven by spin-orbital exchange interactions, as described by the Kugel-Khomskii model. Spinel vanadates, in which orbital degrees of freedom…
The compound $Nb_{5-\delta}Te_4$ ($\delta=0.23$) with quasi-one-dimensional crystal structure undergoes a transition to superconductivity at $T_c$=0.6--0.9 K. Its electronic transport properties in the normal state are studied in the…
In this study, we investigated theoretically the Mott-insulating phase of a deficient spinel chalcogenide GaV$_4$S$_8$, which is known to form a tetrahedral V$_4$S$_4$ cluster unit that results in molecular orbitals (MOs) with a narrow…
We present the result of an extended experimental characterization of the hexagonal intermetallic Haucke compound NpNi$_{5}$. By combining macroscopic and shell-specific techniques, we determine the 5$f$-shell occupation number $n_f$ close…