Related papers: Charge multipoles correlations and order in Cs$_2$…
The physical properties of the single-crystalline samples of Lu_{2} Ir_{3} Si_{5} have been investigated by magnetic susceptibility, resistivity and heat capacity studies. We observed multiple charge density wave (CDW) transitions in all…
We formulate a theory of double perovskite coumpounds such as Sr$_2$FeReO$_6$ and Sr$_2$FeMoO$_6$ which have attracted recent attention for their possible uses as spin valves and sources of spin polarized electrons. We solve the theory in…
Structural phase transitions in $f$-electron materials have attracted sustained attention both for practical and basic science reasons, including that they offer an environment to directly investigate relationships between structure and the…
The subtle interplay between spin-orbit coupling, exchange interactions, and cation ordering can lead to exotic magnetic states in transition-metal ions. We report a comprehensive study of the Re-based (5$d^1$) ordered double perovskite…
Topological physics and strong electron-electron correlations in quantum materials are typically studied independently. However, there have been rapid recent developments in quantum materials in which topological phase transitions emerge…
Out-of-plane and in-plane electric polarization, which rarely coexist in a two-dimensional (2D) ferroelectric material, offer different advantages in ferroelectricity-based devices. Here, we report the coexistence of in-plane and…
We report time-of-flight neutron spectroscopic and diffraction studies of the 5$d^2$ cubic double pervoskite magnets, Ba$_2$MOsO$_6$ ($M$ = Zn, Mg, Ca). These cubic materials are all described by antiferromagnetically-coupled 5$d^2$…
Roles of multipole degrees of freedom in multiband superconductors are investigated in a case of impurities whose low-lying states consist of singlet ground and triplet excited states, which is related to the experimental fact that the…
We report results of high-resolution measurements of the \emph{c$^*$}-axis expansivity ($\alpha_{c^{*}}$) at the charge-ordering (CO) transition for the quasi-1D (TMTTF)$_{2}$X compounds with X = SbF$_6$ and Br and make a comparison with…
Double perovskite-based magnets wherein frustration and competition between emergent degrees of freedom are at play can lead to novel electronic and magnetic phenomena. Herein, we report the electronic structure and magnetic properties of…
By means of Monte Carlo simulations, using finite size scaling and conformal transformations, evidences of a topological phase transition in liquid crystals in two dimensions are reported. A paramagnetic phase appears at high temperature…
Electron pairing and ferromagnetism in various cluster geometries are studied with emphasis on tetrahedron and square pyramid under variation of interaction strength, electron doping and temperature. These exact calculations of charge and…
It is argued that both transitions observed in 50%-doped manganites, at the N\'{e}el temperature ($T_{\rm N}$) and the so-called charge ordering temperature ($T_{\rm CO}$), are magnetic. $T_{\rm N}$ corresponds to the order-disorder…
In this sturdy, we determine the roles of two successive phase transitions in the new spin-Peierls system TiOBr by electron and synchrotron X-ray diffraction analyses. Results show an incommensurate superstructure along the h- and…
Based on an effective QCD Lagrangian we discuss the properties of charge density fluctuations in the vicinity of chiral phase transition. We explore thermodynamics in the presence of spinodal phase separation. We show that appearance of…
The pressure-temperature phase diagram of an intermediate-valence compound YbPd was revealed via simultaneous ac-calorimetry and electrical resistivity measurements. Two successive structural phase transition temperatures, $T_1$ = 125 K and…
The charge spin-separation, pseudogap formation and phase diagrams are studied in two and four site Hubbard clusters using analytical diagonalization and grand canonical ensemble method in a multidimensional parameter space of temperature,…
We construct and analyze a microscopic model for insulating rock salt ordered double perovskites, with the chemical formula A$_2$BB'O$_6$, where the B' atom has a 4d$^1$ or 5d$^1$ electronic configuration and forms a face centered cubic…
A spin-fermion model that captures the charge-transfer properties of Cu-based high critical temperature superconductors is introduced and studied via Monte Carlo simulations. The strong Coulomb repulsion among $d$-electrons in the Cu…
We present a detailed study on the charge ordering (CO) transition in GdBaCo2O5 system by combining high resolution synchrotron powder/single crystal diffraction with electron paramagnetic resonance (EPR) experiments as a function of…