A study of inelastic electron–phonon interactions on tunneling magnetoresistance of a nano-scale device

Abstract

In this research, we have studied the effect of inelastic electron–phonon interactions on current–voltage<br><br>characteristic and tunneling magnetoresistance of a polythiophene molecule that is sandwiched between<br><br>two cobalt electrodes using modified Green’s function method as proposed by Walczak. The molecule is<br><br>described with a modified Su–Schrieffer–Heeger Hamiltonian. The ground state of the molecule is<br><br>obtained by Hellman–Feynman theorem. Electrodes are described in the wide-band approximation and<br><br>spin-flip is neglected during conduction. Our calculation results show that with increase in voltage the<br><br>currents increase and tunneling magnetoresistance decreases. Change in tunneling magnetoresistance<br><br>due to inelastic interactions is limited in a small bias voltage interval and can be neglected in the other bias<br><br>voltages.