Self-Sustained Current Oscillations in a Multi-Quantum-Well Spin Polarized Structure with Normal Contacts

Self-sustained current oscillations (SSCO) are found in a nonlinear electron spin dynamics model of a n-doped dc voltage biased semiconductor II&-VI multi-quantum well structure (MQWS) having one or more of its wells doped with Mn. Provided one well is doped with magnetic impurities, spin polarized current can be obtained even if normal contacts have been attached to this nanostructure. Under certain conditions, the system exhibits static electric field domains and stationary current or moving domains and time-dependent oscillatory current. We have found SSCO for nanostructures with four or more QWs. The presence of SSCO depends on the spin-splitting induced by both, the exchange interaction and the external magnetic field. We also calculate the minimal doping density needed to have SSCO, and a bound above which SSCO disappear. This range is crucial to design a device behaving as a spin polarized current oscillator. [Número especial sobre: Trends in Nanotechnology]

Self-Sustained Current Oscillations in a Multi-Quantum-Well Spin Polarized Structure with Normal Contacts Articles