相关论文: Ferroelectricity induced by cooperative orbital or…

Ferroelectricity, a hallmark of spontaneous inversion-symmetry breaking, has been a central concept in condensed matter physics and functional materials research, yet recent discoveries are revealing that switchable polarization can emerge…

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…

Although multiferroics have undergone extensive examination for several decades, the occurrence of ferroelectricity induced by orbital order is only scarcely documented. In this study, we propose the existence of spontaneous ferroelectric…

The ferroelectricity of multiferroics induced by spin order is commonly explained by considering either purely electronic or ion-displacement contribution. However, there is no general model which includes both effects simultaneously. Here,…

Aiming at understanding the origin of the electronic contribution to ferroelectric polarization in undoped manganites, we evaluate the Berry phase of orbital-polarizable Bloch electrons as an orbital ordering (OO) establishes in the…

We uncover a new pathway towards multiferroicity, showing how magnetism can drive ferroelectricity without relying on inversion symmetry breaking of the magnetic ordering. Our free-energy analysis demonstrates that any commensurate…

It was recently observed that materials showing most striking multiferroic phenomena are frustrated spin-density-wave magnets. We present a simple phenomenological theory, which describes the orientation of the induced electric polarization…

Proposing a general formulism in terms of local coordinates representing the tilting of the ligands' octahedra, we evaluate the electric polarization in a chain of transition metal ions with unpolar octahedron rotation. We find the orbital…

Using first principles calculations, we study the microscopic origin of ferroelectricity (FE) induced by magnetic order in the orthorhombic HoMnO3. We obtain the largest ferroelectric polarization observed in the whole class of improper…

A systematic microscopic theory of magnetically induced ferroelectricity and lattice modulation is presented for all electron configurations of Mott-insulating transition-metal oxides. Various mechanisms of polarization are identified in…

Multiferroics, showing simultaneous ordering of electrical and magnetic degrees of freedom, are remarkable materials as seen from both the academic and technological points of view. A prominent mechanism of multiferroicity is the…

The noncollinear cycloidal magnetic order breaks the inversion symmetry in CaMn$_{7}$O$_{12}$, generating one of the largest spin-orbit driven ferroelectric polarizations measured to date. In this Letter, the microscopic origin of the…

Using first-principles calculations, we predict that tunable ferroelectricity can be realized in oxide perovskites with the Grenier structure and ordered oxygen vacancies. Specifically, we show that $R_{1/3}A_{2/3}\mathrm{FeO}_{2.67}$…

By applying Berry-phase theory for the effective half-filled Hubbard model, we derive an analytical expression for the electronic polarization driven by the relativistic spin-orbit (SO) coupling. The model itself is constructed in the…

The possibility of multiferroicity arising from charge ordering in LuFe2O4 and structurally related rare earth ferrites is reviewed. Recent experimental work on macroscopic indications of ferroelectricity and microscopic determination of…

Metal-organic frameworks comprehend a wide class of hybrid organic-inorganic materials with general structure A$_m$BX$_n$, with $A$ and $X$ being organic molecules and B a metal cation. This often results in enhanced structural flexibility…

Within the broad class of multiferroics (compounds showing a coexistence of magnetism and ferroelectricity), we focus on the subclass of "improper electronic ferroelectrics", i.e. correlated materials where electronic degrees of freedom…

By means of first-principles simulations, we unambiguously show that improper ferroelectricity in magnetite in the low-temperature insulating phase is driven by charge-ordering. An accurate comparison between monoclinic ferroelectric Cc and…

Ferroic transition metal oxides, which exhibit spontaneous elastic, electrical, magnetic or toroidal order, exhibit functional properties that find use in ultrastable solid-state memories to sensors and medical imaging technologies. To…

We studied the ferroelectricity of magnetic oxides in which its emergence coincides with the onset of a second incommensurate magnetic order. We solved for the wave function of e_{g} electrons in the presence of magnetic orders. The…