Related papers: Dynamic Jahn-Teller Phenomena in Heavy Transition …
Complex oxides with $4d$ and $5d$ transition-metal ions recently emerged as a new paradigm in correlated electron physics, due to the interplay between spin-orbit coupling and electron interactions. For $4d$ and $5d$ ions, the spin-orbit…
A model interaction is proposed in which pairing is caused by a non-local Jahn-Teller (JT) -like instability due to the coupling between planar O states and knot equal to 0 phonons. Apart from pairing, the interaction is found to naturally…
Ordering and quantum fluctuations of orbital degrees of freedom are studied theoretically for LaVO$_3$ in spin-C-type antiferromagnetic state. The effective Hamiltonian for the orbital pseudospin shows strong one-dimensional anisotropy due…
Strong electron-electron interaction can induce Mott insulating state, which is believed to host unusual correlated phenomena such as quantum spin liquid when quantum fluctuation dominates and unconventional superconductivity through…
Through 13C NMR spin lattice relaxation (T1) measurements in cubic Na2C60, we detect a gap in its electronic excitations, similar to that observed in tetragonal A4C60. This establishes that Jahn-Teller distortions (JTD) and strong…
In resonant inelastic x-ray scattering (RIXS) spectra of K$_2$IrCl$_6$, the peak for the $j=3/2$ multiplet states shows a splitting that resembles non-cubic crystal-field effect although the compound is cubic down to 0.3 K. Here we…
We present a theoretical study of a possibility of superconductivity in a three dimensional molecular conductor in which the interaction between electrons in doubly degenerate molecular orbitals and an {\em intra}molecular vibration mode is…
Using density-functional theory (DFT) and its extension to DFT+$U$, we propose a possible scenario for a strain-induced metal-insulator transition which has been reported recently in thin films of SrCrO$_3$. The metal-insulator transition…
Generally, in case of the collective Jahn-Teller effect, a high-symmetry structure of a matrix in which quantum systems with degenerate ground state are inserted becomes distorted. This usually smooth transition can become abrupt only if…
The role of elastic interactions between Jahn-Teller ions in formation of various orbital- and charge-ordered structures in manganites and related compounds is analyzed. It is shown that such interactions alone are often sufficient to…
We have theoretically studied successive transitions in vanadium spinel oxides with (t_2g)^2 electron configuration. These compounds show a structural transition at ~ 50K and an antiferromagnetic transition at ~ 40K. Since threefold t_2g…
We review some theoretical aspects connected with the interplay of strong electron correlations and vibron phenomena in negative fullerene ions and in solid fulleride conductors, superconductors and insulators. The first part covers…
The electronic properties of many transition metal oxide systems require new ideas concerning the behaviour of electrons in solids for their explanation. A recent example, subsequent to that of cuprate superconductors, is of rare earth…
It is demonstrated that under common conditions a molecular solid subject to Jahn-Teller interactions supports stable Q-ball-like non-topological solitons. Such solitons represent a localized lump of excess electric charge in periodic…
Narrow-band conductors may turn insulating and magnetic as a consequence of strong electron-electron correlation. In molecular conductors, the concomitance of a strong Jahn-Teller coupling may give rise to the alternative possibility of a…
Short-range resonating-valence bond states in an orbitally degenerate magnet on a honeycomb lattice is studied. A quantum-dimer model is derived from the Hamiltonian which represents the superexchange interaction and the dynamical…
High-pressure optical-absorption measurements performed in CuWO4 up to 20 GPa provide experimental evidence of the persistence of the Jahn-Teller (JT) distortion in the whole pressure range both in the low-pressure triclinic and in the…
Metal insulator transitions driven by local Coulomb interactions are among the most fascinating phenomena in condensed matter physics. They occur in a large variety of transition metal compounds. Most of these strongly correlated materials…
Artificial atom qubits in diamond have emerged as leading candidates for a range of solid-state quantum systems, from quantum sensors to repeater nodes in memory-enhanced quantum communication. Inversion-symmetric group IV vacancy centers,…
We report the temperature dependent mid- and near-infrared spectra of K4C60, Rb4C60 and Cs4C60. The splitting of the vibrational and electronic transitions indicates a molecular symmetry change of C604- which brings the fulleride anion from…