Effects of the Rashba spin-orbit coupling on low-dimensional electron correlated systems

JOSÉ A. RIERA

Rosario

Congreso; IX Encuentro Informal de Materia Condensada; 2014

Instituto de Física Rosario -CONICET

In the first part, the competition between Hubbard repulsion, U, andRashba spin-orbit coupling (RSOC), VSO, is studied on two-leg laddersby numerical techniques. It is found that the RSOC contribution topersistent currents in closed rings for a fixed value of U reaches amaximum at intermediate values of VSO. By increasing the repulsiveHubbard coupling this spin-flipping current is suppressed and eventuallybecomes opposite to the spin-conserving current. The main result is thatthe spin accumulation defined as the relative spin polarization betweenthe two legs of the ladder is enhanced by U. It is also interesting acombined effect leading to an enhancement of antiferromagnetic order whichin turn may explain the observed behavior of the spin-flipping current.In the second part, the ferromagnetic Kondo lattice model (FKLM) in thepresence of a Rashba spin-orbit coupling is examined in two dimensions.Under the assumption that electron spins on localized orbitals may betreated as classical continuum spins, we compute various charge, spinand transport properties at zero temperature. We find that the maineffect of the RSOC is the destruction of the ferromagnetic state presentin the FKLM at low electron fillings, with the consequent suppression ofthe conductivity. In addition, near half-filling the RSOC leads to adeparture of the antiferromagnetic state of the FKLM with a consequentreduction to the intrinsic tendency to electronic phase separation.