Continuous first-order orbital order–disorder transition in Nd1−xCaxMnO3

Continuous First-Order Constraint Satisfaction

This paper shows how to use constraint programming techniques for solving first-order constraints over the reals (i.e., formulas in the first-order predicate language over the structure of the real numbers). More specifically, based on a narrowing operator that implements an arbitrary notion of consistency for atomic constraints over the reals (e.g., box-consistency), the paper provides a narro...

Explorer Metal - Insulator Transition and Orbital Order in PbRuO 3

Orbital order in classical models of transition-metal compounds

– We study the classical 120-degree and related orbital models. These are the classical limits of quantum models which describe the interactions among orbitals of transitionmetal compounds. We demonstrate that at low temperatures these models exhibit a long-range order which arises via an “order by disorder” mechanism. This strongly indicates that there is orbital ordering in the quantum versio...

Continuous versus First Order Transition in Dilute Ising Antiferromagnets in a Field

A systematic Monte Carlo investigation of dilute Ising antiferromagnets in a uniform field as function of both dilution and ratio a! of nnn to nn interactions on a cubic lattice is presented. A tricritical point is found in the range of dilution 0 5 p 5 0.3 for a ratio a = -0.5. Increasing p makes the first order region to shrink. On the other hand increasing or enlarges it. We present a new pr...

A first-order Mott transition in LixCoO2.

Despite many years of experimental searches for a first-order Mott transition in crystalline-doped semiconductors, none have been found. Extensive experimental work has characterized a first-order metal-insulator transition in Li(x)CoO(2), the classic material for rechargeable Li batteries, with a metallic state for x < 0.75 and insulating for x > 0.95. Using density functional theory calculati...