Recent content by rejinisaac1

positive MR was achieved with Fe. no MR was observed in case of just CNTs. positive MR was observed when CNT concentration was fixed and Fe increased and also when Fe concentration was fixed and CNT increased. what could be the reason??

magnetostriction in Fe is negligible...MR is increasing with increase in CNT

I've achieved positive magnetoresistance (MR) in CNT composite thin films with a small percentage of Fe in it. Fe injects spin polarized electrons into CNT. But +ve MR means that resistance is increasing with magnetic field. But due to injection of spin polarized electrons the current has to...

Thanks for the replies. Though I wrote 'lead self energies', it was the coupling matrices that I was referring to. But I still have a doubt \Gamma _{s} = i (\Sigma_{s} - \Sigma_{s}^{\dagger}) , \Gamma _{d} = i (\Sigma_{d} - \Sigma_{d}^{\dagger}) , T(E)=Tr\left[\Gamma...

I am working on tight binding formulation of CNTs. The transmission function T(E), which is the trace of the product of the lead self energies and the retarded and advanced green's function. This value is a complex entity. T(E) needs to be calculated at different energy levels and then...

The equation of the allowed wave vectors for a CNT is given by K= k*( K1/|K1|) + nK2 -pi/T< k <=pi/T n=0,1,2,3...N How does one construct K ? Run a loop of k from -pi/T to pi/T for a given value of n?

i was referring to this book named 'physical properties of carbon nanotubes' by saito and dresselhaus. Page 47 of this book shows 2 vectors K1 and K2. The allowed vectors are shown parallel to K1. So are the values of K1 the allowed wave vectors of the in the first brillouin zone of the CNT...

how does one find the allowed wave vectors in a CNT? I'm trying to use an sp3s* tight binding approach to compute the current through a CNT. While writing the off diagonal elements, is exp^{ik.R} a necesaary prefix? If so what value of k does one have to take?