Tunable disorder and localization in the rare-earth nickelates

Multiferroicity in rare-earth nickelates RNiO3.

We show that charge ordered rare-earth nickelates of the type RNiO3 (R = Ho, Lu, Pr and Nd) are multiferroic with very large magnetically-induced ferroelectric (FE) polarizations. This we determine from first principles electronic structure calculations. The emerging FE polarization is directly tied to the long-standing puzzle of which kind of magnetic ordering is present in this class of mater...

Site-selective Mott transition in rare-earth-element nickelates.

A combination of density functional and dynamical mean field theory calculations are used to show that the remarkable metal-insulator transition in the rare-earth-element nickelate perovskites arises from a site-selective Mott phase, in which the d electrons on half of the Ni ions are localized to form a fluctuating moment while the d electrons on other Ni ions form a singlet with holes on the ...

Dilution-controlled quantum criticality in rare-earth nickelates.

A microscopic model for the diluted spin-mixed compounds (RxY1-x)2BaNiO5 (R=magnetic rare earth) is studied using quantum Monte Carlo simulations. The ordering temperature is shown to be a universal function of the impurity concentration x and the intrinsic Ni-chain correlation length. An effective model for the critical modes is derived. The possibility of a quantum critical point driven by th...

Tunable Rare-Earth Doped Fiber Laser

Ground-state oxygen holes and the metal–insulator transition in the negative charge-transfer rare-earth nickelates

The metal-insulator transition and the intriguing physical properties of rare-earth perovskite nickelates have attracted considerable attention in recent years. Nonetheless, a complete understanding of these materials remains elusive. Here we combine X-ray absorption and resonant inelastic X-ray scattering (RIXS) spectroscopies to resolve important aspects of the complex electronic structure of...