Electronic structure of negative charge transfer CaFeO3 across the metal-insulator transition

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...

Spin valve effect across the metal-insulator transition in V2O3

The magnetoresistance of Ni/V2O3/Py devices shows interesting behavior in the temperature dependence across the V2O3 metal-insulator transition. A spin-valve effect ( 0.1%) is found below the transition temperature when V2O3 is in the insulating phase. Contrary to expectation, the spin-valve effect disappears when device is heated above 150 K and V2O3 is in the metallic state. At these temperat...

Aging effects across the metal-insulator transition in two dimensions.

Aging effects in the relaxations of conductivity of a two-dimensional electron system in Si have been studied as a function of carrier density. They reveal an abrupt change in the nature of the glassy phase at the metal-insulator transition (MIT): (a) while full aging is observed in the insulating regime, there are significant departures from full aging on the metallic side of the MIT, before t...

Microscopic structure of the metal-insulator transition in two dimensions.

A single electron transistor is used as a local electrostatic probe to study the underlying spatial structure of the metal-insulator transition in two dimensions. The measurements show that as we approach the transition from the metallic side, a new phase emerges that consists of weakly coupled fragments of the two-dimensional system. These fragments consist of localized charge that coexists wi...

Dynamics of electronic transfer processes at metal/insulator interfaces.