Related papers: Charge and Spin Ordering in the Mixed Valence Comp…
A quantum interference mechanism of the stripe phase instability in quasi one-dimensional (1D) repulsive electron system is proposed. The leading spin-charge coupling term in Landau functional is derived microscopically. It is shown that…
We consider a two-layer Heisenberg antiferromagnet which can be either in the N\'{e}el-ordered or in the disordered phase at $T=0$, depending on the ratio of the intra- and interlayer exchange constants. We reduce the problem to an…
Resonant soft X-ray scattering was used to determine the presence of more subtle orderings not detected in standard structural analyses. By tuning to specific Co absorption edges, arrangements particular to the electronic states of those…
Ferroelectric and ferromagnetic materials possess spontaneous electric and magnetic order, respectively, which can be switched by the corresponding applied electric and magnetic fields. Multiferroics combine these properties in a single…
MnV$_2$O$_4$ in the spinel structure is known to exhibit coupled orbital and spin ordering, and its Raman spectra show interesting anomalies in its low-temperature phase. With a goal to explain this behavior involving coupled spins and…
We report a neutron diffraction study of the multiferroic mechanism in (ND4)2FeCl5D2O, a molecular compound that exhibits magnetically induced ferroelectricity. This material exhibits two successive magnetic transitions on cooling: a…
We study numerically the one dimensional ferromagnetic Kondo lattice, a model widely used to describe nickel and manganese perovskites. By including a nearest neighbor Coulomb interaction (V) and a superexchange interaction between the…
We present our theoretical results on the ground states in layered triangular-lattice compounds ANiO2 (A=Na, Li, Ag). To describe the interplay between charge, spin, orbital, and lattice degrees of freedom in these materials, we study a…
We study theoretically low-temperature phases of a recently synthesized compound Sr$_2$CoO$_3$F under pressure. The analysis combining LDA+DMFT and a strong-coupling effective model points to the existence of not only normal paramagnetic…
We report on Raman scattering measurements of the A-site ordered YBaMn2O6 in the wide temperature range of 10-650K. Upon cooling almost all phonon modes show pronounced temperature dependencies of frequency, linewidth, and scattering…
Theoretical account is given of 4f-electron dynamics and multipole orders in Pr skutterudites with particular attention to (i) mechanism of the crystalline electric field (CEF) splitting leading to a pseudo-quartet ground state;(ii) Kondo…
Temperature and magnetic field studies of the elastic constants of the chromium spinel CdCr_2O_4 show pronounced anomalies related to strong spin-phonon coupling in this frustrated antiferromagnet. A detailed comparison of the longitudinal…
The nature of the charge order in the charge frustrated compound LuFe$_2$O$_4$ and its effect on magnetocapacitance were examined on the basis of first-principles electronic structure calculations and Monte Carlo simulations of…
Lattice effects on photo-excited states in interacting charge frustrated system are examined. Real time dynamics in the interacting spinless fermion model on a triangular lattice coupled to lattice vibration are analyzed by applying the…
We investigated the series of temperature and field-driven transitions in LuFe$_2$O$_4$ by optical and M\"{o}ssbauer spectroscopies, magnetization, and x-ray scattering in order to understand the interplay between charge, structure, and…
Spinel structured compounds, $AB_2O_4$, are special because of their exotic multiferroic properties. In $ACr_2O_4$ ($A$=$Co$, $Mn$,$Fe$), a switchable polarization has been observed experimentally due to a non-collinear magnetic spin order.…
The Kondo lattice model plays a key role in our understanding of quantum materials, but a lack of small parameters has posed a long-standing problem. We present a 3 dimensional S= 1/2 Kondo lattice model describing a spin liquid within an…
The ground state of the frustrated A-site magnetic spinel CoAl2O4 has been a controversial issue whether it is a collinear antiferromagnetic ordering or a spiral spin - liquid state, as the ratio of the two competing interactions, J2/J1…
The insulating ternary oxide YbFe$_2$O$_4$ displays an unusual frustration-driven incommensurate charge-ordering (CO) transition, linked to possible ferroelectricity. Based on high-resolution synchrotron data, we report a detailed…
Magnetic frustrations and degeneracies profoundly affect ground-state magnetic properties emerging from competing exchange interactions. Controlling such frustrations using orbital and phonon engineering via the Kugel-Khomskii-type…