Current and Shot Noise Measurements in a Carbon Nanotube-Based Spin Diode

TL;DR

This study investigates current and shot noise in asymmetric carbon nanotube quantum dots with ferromagnetic and normal-metal contacts, revealing spin-dependent rectification and noise suppression at resonant conditions.

Contribution

It provides new insights into spin-dependent transport and noise characteristics in CNT quantum dots with asymmetric contacts, highlighting the effects of resonance and device asymmetry.

Findings

Spin-dependent rectification observed in CNT quantum dots.

Shot noise decreases significantly at maximum current points.

Resonance with quantum dot levels influences noise behavior.

Abstract

Low-temperature measurements of asymmetric carbon nanotube (CNT) quantum dots are reported. The CNTs are end-contacted with one ferromagnetic and one normal-metal electrode. The measurements show a spin-dependent rectification of the current caused by the asymmetry of the device. This rectification occurs for gate voltages for which the normal-metal lead is resonant with a level of the quantum dot. At the gate voltages at which the current is at the maximum current, a significant decrease in the current shot noise is observed.