Importance of electron–electron interactions and Zeeman splitting in single-wall carbon nanotube quantum dots

We present experimental results on the low-temperature transport of an individual single-wall carbon nanotube (SWNT) quantum dot. A variety of features in the Coulomb diamonds have been observed, such as a distortion of Coulomb diamonds as well as standard diamonds with a rectangular shape, depending on a gate voltage range. Magnetic field studies have revealed the simple Zeeman splitting of single particle states in some gate voltage ranges and a spin polarization in the dot in other gate voltage range. Our results suggest the importance of electron–electron interactions and the single particle states which move differently with a gate voltage.