From Transparent Conduction to Coulomb Blockade at Fixed Hole Number

• Published in: physica status solidi (b) Vol. 257; no. 12
• Main Authors: Schmid, Daniel R., Stiller, Peter L., Dirnaichner, Alois, Hüttel, Andreas K.
• Format: Journal Article
• Language: English
• Published: 01.12.2020
• Subjects: carbon nanotubes; Coulomb blockade; Fabry–Pérot interference; Kondo effect; mixed valence regime; quantum dots
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.202000253

A complex set of transport spectroscopy data on a clean single‐wall carbon nanotube device in high magnetic fields is presented. At zero axial field, the device displays in hole conduction with increasingly negative gate voltage a fast transition toward high contact transparency and eventually Fabry–Pérot interference of conductance. When increasing the axial field component up to B∥=17 T, the contact transparency and the overall conductance are reduced all the way to Coulomb blockade, clearly displaying the subsequent charging with the first ten holes. The continuous transition between the transport regimes is dominated by a rich spectrum of Kondo‐like resonances, with distinct features in the stability diagrams. At low temperatures, carbon nanotubes can act as ballistic conductors and electron waveguides, but also near‐perfect traps for artificial atom‐like bound electronic states. Herein, measurements that tune the conductance all the way between these extremes are presented, using a magnetic field only and keeping the charge constant. Coulomb oscillations are directly connected to Fabry–Pérot like interference patterns.