Magnetic interactions and spin polarized transport in magnetic quantum dots

• Grant number: 07/05783-2
• Support Opportunities: Regular Research Grants
• Start date: February 01, 2008
• End date: July 31, 2010
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: José Carlos Egues de Menezes
• Grantee: José Carlos Egues de Menezes
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

Here we present research plans to investigate quantum transport through a magnetic quantum dot -- with (spin 5/2) Mn impurities embedded and interacting electrons -- coupled to ferromagnetic leads. Basically, we shall investigate the electron-electron interactions effects (i) on the elecron-Mn coupling (i.e.the s-d exchange), (ii) on the Mn-Mn coupling, and (iii) we shall also study how the effects in (i) and (ii) affect, for instance, the resonant tunneling through the quantum dot. We will consider a variety of systems: single dots with several electrons and a single Mn impurity as well as with two impurities, double quantum dots coupled in series and in parallel also containing interacting electrons and one, two or more magnetic impurities. Initially we will study in detail the electronic structure of two-dimensional quantum dots by solving the Schrödinger equation of the system in an appropriate basis ("configuration interaction") via exact diagonalization. From these results we will determine the relevant parameters (e.g., s-d exchange constant and tunneling rates) for the quantum master equation model, directly derived from the Hamiltonian of the system. Possible extensions, generalizations, and additional studies involve, for instance, the inclusion of spin-orbit interaction effects, the calculation of the quantum shot noise, and the determination of the electronic structure of the dots via Spin Density Functional Theory. (AU)