Related papers: Ferroelectricity induced by cooperative orbital or…
The ferroelectric polarization of triangular-lattice antiferromagnets induced by helical spin-spiral order is not explained by any existing model of magnetic-order-driven ferroelectricity. We resolve this problem by developing a general…
Orbital angular momentum and torque transfer play central roles in a wide range of magnetic textures and devices including skyrmions and spin-torque electronics(1-4). Analogous topological structures are now also being explored in…
Large electron-electron Coulomb-interactions in correlated systems can lead to a periodic arrangement of localized electrons, the so called "charge-order". The latter is here proposed as a driving force behind ferroelectricity in iron…
We present a strategy to design structures for which a polar lattice distortion induces weak ferromagnetism. We identify a large class of multiferroic oxides as potential realizations and use density-functional theory to screen several…
By performing accurate ab-initio density functional theory calculations, we study the role of $4f$ electrons in stabilizing the magnetic-field-induced ferroelectric state of DyFeO$_{3}$. We confirm that the ferroelectric polarization is…
Multiferroics, where two or more ferroic order parameters coexist, is one of the hottest fields in condensed matter physics and materials science[1-9]. However, the coexistence of magnetism and conventional ferroelectricity is physically…
The switching polarization of a ferroelectric is a characterization of the current that flows due to changes in polarization when the system is switched between two states. Computation of this change in polarization in crystal systems has…
We show by means of ab-initio calculations that the organic molecular crystal TTF-CA is multiferroic: it has an instability to develop spontaneously both ferroelectric and magnetic ordering. Ferroelectricity is driven by a Peierls…
We have investigated the variation of induced ferroelectric polarization under magnetic field with various directions and magnitudes in a staggered antiferromagnet Ba$_2$CoGe$_2$O$_7$. While the ferroelectric polarization cannot be…
By studying the dielectric properties of the geometrically frustrated spinel CdV2O4, we observe ferroelectricity developing at the transition into the collinear antiferromagnetic ground state. In this multiferroic spinel, ferroelectricity…
Realization of ferromagnetic ferroelectricity, combining two ferroic orders in a single phase, is the longstanding problem of great practical importance. One of the difficulties is that ferromagnetism alone cannot break inversion symmetry…
Ferroelectric HfO$_2$ has emerged as a highly promising material for high-density nonvolatile memory and nanoscale transistor applications. However, the uncertain origin of polarization in HfO$_2$ limits our ability to fully understand and…
Multiferroics, defined for those multifunctional materials in which two or more kinds of fundamental ferroicities coexist, have become one of the hottest topics of condensed matter physics and materials science in recent years. The…
In this contribution to the special issue on multiferroics we focus on multiferroicity driven by different forms of charge ordering. We will present the generic mechanisms by which charge ordering can induce ferroelectricity in magnetic…
We consider the impact of Berry phase on the Wigner crystal (WC) state of a two-dimensional electron system. We consider first a model of Bernal bilayer graphene with a perpendicular displacement field, and we show that Berry curvature…
This letter addresses basic questions concerning ferroelectric order in positionally disordered dipolar materials. Three models distinguished by dipole vectors which have one, two or three components are studied by computer simulation.…
Orbitally ordered states evolving coincidentally with structural distortions and magnetic ordering provide a novel route to controlling electronic and magnetic properties of materials through external fields. We report an unprecedented…
We performed first principles calculations for epitaxially strained orthorhombic CaTiO$_3$. The computational results reveal the existence of a metastable ferroelectric phase at compressive strain with unexpected in-plane polarization.…
The first switchable electric polarization in metals was recently discovered in bilayer and trilayer WTe2. Strangely, despite the tininess of the ordered polarization, the ferroelectricity survives up to 350 K, rendering the mechanism of…
A simple but general microscopic mechanism to understand the interplay between the electric and magnetic degrees of freedom is developed. Within this mechanism, the magnetic structure generates an electric current which induce an…