Interplay of spin–orbit coupling and Zeeman effect probed by Kondo resonance in a carbon nanotube quantum dot

The spin orbit interaction in a carbon nanotube is probed by Kondo resonance. Spin orbit interaction lifts level degeneracy and leads to additional satellite current peaks along with the zero-bias Kondo resonance peak. From the positions of satellite peaks, the spin–orbit interaction energy Δso is determined to be 0.38 meV. In the presence of a parallel magnetic field, the satellite peaks split into two; one follows spin-Zeeman dependence with a g-factor of 1.91 and the other one follows orbital-Zeeman dependence with a 2μorb value of 170 μeV/T. The zero-bias Kondo resonance peak also displays a spin-Zeeman dependence but has an offset in magnetic field of 2.25 T, consistent with the value of Δso/2μorb obtained independently.