Modeling a Schottky-barrier carbon nanotube field-effect transistor with ferromagnetic contacts

TL;DR

This paper models a Schottky-barrier CNT-FET with ferromagnetic contacts, analyzing its electrical noise and magnetoresistance, revealing significant dependence on contact magnetization orientation and potential for high tunnel magnetoresistance.

Contribution

It introduces a detailed model of a ferromagnetic-contact CNT-FET using tight-binding and Green's function methods, highlighting the impact of magnetic alignment on transport and noise.

Findings

Shot noise is Poissonian in the sub-threshold region.

Fano factor decreases at higher voltages.

Tunnel magnetoresistance can exceed 50%.

Abstract

In this study, a model of a Schottky-barrier carbon nanotube field- effect transistor (CNT-FET), with ferromagnetic contacts, has been developed. The emphasis is put on analysis of current-voltage characteristics as well as shot (and thermal) noise. The method is based on the tight-binding model and the non- equilibrium Green's function technique. The calculations show that, at room temperature, the shot noise of the CNT FET is Poissonian in the sub-threshold region, whereas in elevated gate and drain/source voltage regions the Fano factor gets strongly reduced. Moreover, transport properties strongly depend on relative magnetization orientations in the source and drain contacts. In particular, one observes quite a large tunnel magnetoresistance, whose absolute value may exceed 50%.