The Role of Electron-Phonon Coupling in Spin Transport through FM-QD Molecular-FM in the Presence of Spin Accumulation in the Leads

Abstract

The spin transport process through quantum dot molecular, embedded between two ferromagnetic leads in parallel configuration with the presence of spin accumulation, is studied by getting use of the non-equilibrium Keldysh – Green’s function technique. The electron-phonon coupling can be implicitly considered in the model, using the canonical transformation where a single phonon mode is considered in the strong electron – phonon coupling regime. Since the heat may interchange between the quantum dot molecular and the phonon bath coupled to it. And as the principle aim of our study is to determine the parameters that afford high spin (charge) heat generation, that must be avoid in the experimental applications, all the spin transport properties are investigated throughout the calculation of the spin and charge accumulation on the quantum dot molecular, the spin polarized currents, the spin and charge currents, the spin polarized heat generations, the spin heat generation and the charge heat generation. The calculations are accomplished as a function of the model calculation parameters that can be tuned experimentally. The spin blockade and the negative differential phenomena are investigated since the spin transport properties are studied extendedly in the case of a parallel configuration in the leads. It is concluded that the operative and functional values of the bias voltage can be determined by single phonon energy and the electron-phonon coupling values. Since all our calculations are accomplished for electron-phonon coupling equals 0.05eV. Finally, we must report the following: in the case of parallel configuration with high spin polarization, the spin heat generation equals the charge heat generation and both are relatively high where the intradot interaction has no role. While, as the spin polarization is lowered then the charge heat generation be greater than the spin heat generation when the correlation energy is relatively low.