Related papers: Machine Learning the order-disorder Jahn-Teller tr…

At room temperature, the normal oxide spinels NiCr_2O_4 and CuCr_2O_4 are tetragonally distorted and crystallize in the I4_1/amd space group due to cooperative Jahn-Teller ordering driven by the orbital degeneracy of tetrahedral Ni$^{2+}$…

The physics of manganites is often described within an effective two-band tight-binding (TB) model for the Mn e_g electrons, which apart from the kinetic energy includes also a local "Hund's rule" coupling to the t_{2g} core spin and a…

This paper reviews recent experimental and theoretical developments of the dynamic Jahn-Teller effect-driven phenomena in heavy transition metal-based spin-orbit Mott insulators. In cubic $4d/5d$ transition metal compounds, the spin,…

First-order phase transitions, characterized by a discontinuous change in the order parameter, are intriguing phenomena in condensed matter physics. However, the underlying, material-specific, microscopic mechanisms often remain unclear.…

The quasi-one-dimensional organic conductors (TMTTF)$_2X$ with non-centrosymmetric anions commonly undergo charge- and anion-order transitions upon cooling. While for compounds with tetrahedral anions ($X$ = BF$_4^-$, ReO$_4^-$, and…

The recent observation of a insulator to metal transition (IMT) [I. Loa et al, PRL 87, 125501 (2001)] in pure LaMnO$_3$ at 32 GPa and room temperature, well above the Neel temperature (145 K) and below the Jahn-Teller transition temperature…

The orbital, lattice, and spin ordering phenomena in KCuF3 are investigated by means of LDA+U calculations, based on ab-initio pseudopotentials.We examine the Cu-3d orbital ordering and the associated Jahn-Teller distortion in several…

Temperature-induced phase transition in BaTiO3 has been explored using the machine learning analysis of domain morphologies visualized via variable-temperature scanning transmission electron microscopy (STEM) imaging data. This approach is…

Jahn-Teller distortions of transition-metal coordination environments link orbital occupancies to structure. In the solid state, such distortions can be strongly correlated through the propagation of strain and/or through orbital…

The high-pressure behaviour of Na$_2$CuF$_4$ is explored by powder neutron diffraction and density functional theory (DFT) calculations. A first-order phase transition is observed to take place between 2.4 - 2.9 GPa, involving a…

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…

Using DFT-based molecular dynamics simulation of Cu$^+$ cations flipping and In$^{3+}$ cations displacive dynamics, we clarify the dipole ordering of CuInP$_2$S$_6$ ferrielectrics through the second order Jahn-Teller effect which determines…

Strained thin films of charge/orbital ordered (CO/OO) $Nd_{0.5}Ca_{0.5}MnO_3$ (NCMO) with various thickness have grown on (100)-SrTiO$_3$ and (100)-LaAlO$_3$ substrates, by using the Pulsed Laser Deposition (PLD) technique. The thickness of…

Transition metal spinel oxides comprised of Earth-abundant Mn and Co have long been explored for their use in catalytic reactions and energy storage. However, understanding of functional properties can be challenging due to differences in…

We use first principles density functional theory to calculate electronic and magnetic properties of TiF3 using the full potential linearized augmented plane wave method. The LDA approximation predicts a fully saturated ferromagnetic metal…

The electronic structure of La0.8Sr0..2MnO3/SrTiO thin film, which was prepared by Laser MBE, was studied by X-ray photoemission spectra (XPS) in the temperature interval of 300 to 1000 K. Experimental results showed that the electronic…

We have studied the antiferromagnetic order -- disorder transition occurring at $T=0$ in a 2-layer quantum Heisenberg antiferromagnet as the inter-plane coupling is increased. Quantum Monte Carlo results for the staggered structure factor…

The first-principles SIC-LSD theory is utilized to study electronic, magnetic and orbital phenomena in LaMnO$_{3}$. The correct ground state is found, which is antiferro orbitally ordered with the spin magnetic moments antiferromagnetically…

The analysis of phonon anomalies provides valuable information about the cooperative dynamics of lattice, spin and charge degrees of freedom. Significant is the anomalous temperature dependence of the external modes observed in…

Three high-spin phases recently discovered in the spin-crossover system Mn(taa) are identified through analysis by a combination of first-principles calculations and Monte Carlo simulation as a low-temperature Jahn-Teller ordered (solid)…