相关论文: Dual Orbital Degeneracy Lifting in a Strongly Corr…

The recent discovery of a local fluctuating t2g orbital-degeneracy-lifted (ODL) state in CuIr2S4 as a high temperature precursor to the metal-insulator transition (MIT) opens the door to a possible widespread presence of precursor states in…

The local structure of the spinel LiRh$_2$O$_4$ has been studied using atomic pair distribution function (PDF) analysis of powder x-ray diffraction data. This measurement is sensitive to the presence of short Rh-Rh bonds that form due to…

Magnetic and electronic properties of NaTiSi$_2$O$_6$ in low temperature phase were studied in the framework of the LDA+U approximation. We stress that neglecting correlation effects in LSDA calculations one obtains not only several times…

Fundamental electronic principles underlying all transition metal compounds are the symmetry and filling of the $d$-electron orbitals and the influence of this filling on structural configurations and responses. Here we use a sensitive…

The lifting of degenerate electronic states, in which multiple electronic states share the same energy, is a fundamental issue in the physics of crystalline solids. In real materials, this problem has been extensively studied in transition…

It has been suggested that the metal-insulator transitions in a number of spinel materials with partially-filled t_2g d-orbitals can be explained as orbitally-driven Peierls instabilities. Motivated by these suggestions, we examine…

We present a band structure study of orbital polarization and ordering in the two-dimensional triangular lattice transition metal compounds LiVO_2 and NaTiO_2. It is found that while in NaTiO_2 the degeneracy of t_{2g} orbitals is lifted…

NaTiSi2O6 is an exemplary compound, showing an orbital assisted spin-Peierls phase transition at Tc = 210 K. We present the results of 29Si and 23Na NMR measurements of NaTiSi2O6. The use of magic angle spinning techniques unambiguously…

Two-dimensional electron liquids (2DELs) have increasing technological relevance for ultrafast electronics and spintronics, yet significant gaps in their fundamental understanding are exemplified on the prototypical SrTiO$_3$. We correlate…

Does the quasi one-dimensional titanium pyroxene NaTiSi2O6 exhibit the novel {\it orbital-Peierls} state? We calculate its groundstate properties by three methods: Monte Carlo simulations, a spin-orbital decoupling scheme and a mapping onto…

We show that in transition metal compounds containing structural metal dimers there may exist in the presence of different orbitals a special state with partial formation of singlets by electrons on one orbital, while others are effectively…

The onset and melting of locally staggered charge/orbital correlations is investigated within a two-orbital correlated electron model with inter-orbital and inter-site Coulomb interactions. Beyond the critical doping concentration x_c ~…

The weakly interacting S=1/2 dimers system Sr3Cr2O8 has been investigated by powder neutron diffraction and inelastic neutron scattering. Our data reveal a structural phase transition below room temperature corresponding to an…

We study with the Raman scattering technique two types of phase transitions in the pyroxene compounds NaMSi$_2$O$_6$ (with M=Ti, V, and Cr). In the quasi one-dimensional S=1/2 system NaTiSi$_2$O$_6$ we observe anomalous high-temperature…

The recently discovered high-$T_c$ superconductivity in La$_{3}$Ni$_{2}$O$_{7}$ with $T_c \approx 80K$ provides another intriguing platform to explore the microscopic mechanism of unconventional superconductivity. In this work, we study a…

We consider the superstructures, which can be formed in spinels containing on B-sites the transition-metal ions with partially filled t2g levels. We show that, when such systems are close to itinerant state (e.g. have an insulator-metal…

We study a system of spinless electrons moving in a two dimensional noncommutative space subject to a perpendicular magnetic field $\vec B$ and confined by a harmonic potential type ${1\over 2}mw_{0}r^2$. We look for the orbital magnetism…

Recently the structural transition in Na2Ti3Cl8 at 200 K with the formation of triangular Ti3 clusters was studied by ab-initio calculations in PRL 124, 167203 (2020). It was concluded on the basis of the DFT+U results that the usual band…

A possible mechanism for the removal of the orbital degeneracy in RTiO3 (where R=La, Y, ...) is considered. The calculation is based on the Kugel-Khomskii Hamiltonian for electrons residing in the t2g orbitals of the Ti ions, and uses a…

The odd-parity spin-triplet Cooper pairing states show a six-fold degeneracy for a quasi-two-dimensional electron system. In this article we show how spin-orbit coupling can lift this degeneracy for Sr_2RuO_4 taking the band structure based…