Magnetic and transport signatures of Rashba spin-orbit coupling on the ferromagnetic Kondo lattice model in two dimensions

Motivated by emergent phenomena at oxide surfaces and interfaces, particularly those involving transition metal oxides with perovskite crystal structure such as LaTiO3/SrTiO3, we examine the ferromagnetic Kondo lattice model (FKLM) in the presence of a Rashba spin-orbit coupling (RSOC). Using numerical techniques, under the assumption that the electrons on localized orbitals may be treated as classical continuum spins, we compute various charge, spin and transport properties on square clusters at zero temperature. We find that the main effect of the RSOC is the destruction of the ferromagnetic state present in the FKLM at low electron fillings, with the consequent suppression of conductivity. In addition, near half-filling the RSOC leads to a departure of the antiferromagnetic state of the FKLM with a consequent reduction to the intrinsic tendency to electronic phase separation. The interplay between phase separation on one side, and magnetic and transport properties on the other, is carefully analyzed as a function of the RSOC/hopping ratio.Comment: final version, accepted for publication in Phys. Rev.

Predicting permeability and flow capacity distribution with back-propagation artificial neural networks

The prediction of permeability is a critical, key step for reservoir modeling and management of oil recovery operations. Previous studies have successfully demonstrated that the new technology called Artificial Neural Network (ANN), a biologically inspired, massive parallel, distributed information processing system, is an excellent tool for permeability predictions using well log data. This technology overcomes the drawbacks caused by the inherent heterogeneity of the reservoir and lack of sufficient cores or pressure transient tests, allowing to define reservoir characterization within an acceptable accuracy while maintaining costs low. The methodology used in this study takes advantage of this technology to accomplish such a task.;An ANN was developed obtaining a correlation coefficient R2 of 0.975 when compared permeability predictions to actual measurements for seven wells using their well log data in a reservoir in West Virginia, USA. Thereafter, the ANN was used to forecast the permeability for the rest of the wells in the reservoir. Thus, based on the well permeability profile, the Flow Capacity and Average Permeability was determined and mapped throughout the field which defined the most productive areas in the reservoir and helped to improve the production history matching

Competing Pairing Symmetries in a Generalized Two-Orbital Model for the Pnictides

We introduce and study an extended "t-U-J" two-orbital model for the pnictides that includes Heisenberg terms deduced from the strong coupling expansion. Including these J terms explicitly allows us to enhance the strength of the (pi, 0)-(0, pi) spin order which favors the presence of tightly bound pairing states even in the small clusters that are here exactly diagonalized. The A1g and B2g pairing symmetries are found to compete in the realistic spin-ordered and metallic regime. The dynamical pairing susceptibility additionally unveils low-lying B1g states, suggesting that small changes in parameters may render any of the three channels stable.Comment: submitted PRL 10/5/1