Superlattice-induced ferroelectricity in charge-ordered La1/3_{1/3}Sr2/3_{2/3}FeO3_{3}

Charge-order-driven ferroelectrics are an emerging class of functional materials, distinct from conventional ferroelectrics, where electron-dominated switching can occur at high frequency. Despite their promise, only a few systems exhibiting this behavior have been experimentally realized thus far, motivating the need for new materials. Here, we use density functional theory to study the effect of artificial structuring on mixed-valence solid-solution La$_{1/3}$Sr$_{2/3}$FeO$_{3}$ (LSFO), a system well-studied experimentally. Our calculations show that A-site cation (111)-layered LSFO exhibits a ferroelectric charge-ordered phase in which inversion symmetry is broken by changing the registry of the charge order with respect to the superlattice layering. The phase is energetically degenerate with a ground-state centrosymmetric phase, and the computed switching polarization is 39 $\mu$C/cm$^{2}$, a significant value arising from electron transfer between Fe ions. Our calculations reveal that artificial structuring of LSFO and other mixed valence oxides with robust charge ordering in the solid solution phase can lead to charge-order-induced ferroelectricity

Parameters of variation between verb-subject and subject-verb order in late Middle English

This article sets out to clarify the contribution of syntactic properties and subject weight for variation between verb-subject and subject-verb order in a database of fourteenth and fifteenth-century prose. It sets out the syntactic structures which are assumed, and investigates the impact on ordering of a set of factors, using established quantitative methodologies. A series of conclusions includes the continuing distinct status of initial then, the systematic importance of clause-final position, the different impacts of subject length in different contexts, and the presence of a definiteness effect for the late placement of a subject after a nonfinite unaccusative

Mechanisms and origin of multiferroicity

Motivated by the potential applications of their intrinsic cross-coupling properties, the interest in multiferroic materials has constantly increased recently, leading to significant experimental and theoretical advancements. From the theoretical point of view, recent progresses have allowed to identify different mechanisms responsible for the appearence of ferroelectric polarization coexisting with -- and coupled to -- magnetic properties. This chapter aims at reviewing the fundamental mechanisms devised so far, mainly in transition-metal oxides, which lie at the origin of multiferroicity

The syntactic derivations of interrogative verbs in Amis and Kavalan

Interrogative words that denote ‘what’, ‘how’, ‘where’, and ‘how many’ in Amis and Kavalan have the same morphosyntactic distribution as verbs. The present paper argues that their use as verbs is not due to unconstrained lexical idiosyncrasies, but exhibits consistent syntactic and semantic patterns. Their grammatical properties and restrictions follow from the interaction of the following factors: the inherent semantics of interrogative words, the available interpretation of the question where they occur, the verbal structures of the voice markers, and the syntactic principles and constraints like the Head Movement Constraint or the Transparence Condition. The syntactic analysis advocated in this paper can extend to other atypical non-interrogative verbs in the two languages and makes falsifiable predictions about what interrogative words can and cannot be used as verbs

Optimal Simple Monetary and Fiscal Rules under Limited Asset Market Participation

The combination of limited asset market participation and consumption habits generates indeterminacy for empirically plausible calibrations of a business cycle model characterized by price and nominal wage rigidities. Equilibrium determinacy is restored by demand management policies based on simple fiscal rules. In this regard, fiscal control of nominal income growth is particularly effective. In addition the complementarity between the Taylor rule and the fiscal feedback on nominal income growth produces relatively large welfare gains, limiting both aggregate and intragroup volatilities