Split-gate quantum point contacts with tunable channel length

Gate-tunable split Kondo effect in a carbon nanotube quantum dot.

We show a detailed investigation of the split Kondo effect in a carbon nanotube quantum dot with multiple gate electrodes. Two conductance peaks, observed at finite bias in nonlinear transport measurements, are found to approach each other for increasing magnetic field, to result in a recovered zero bias Kondo resonance at finite magnetic field. Surprisingly, in the same charge state, but under...

Imaging in Quantum Point Contacts

Alessandro Cresti , Giuseppe Grosso (2) and Giuseppe Pastori Parravicini (3) (1) NEST-INFM, Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy, and Dipartimento di Fisica E. Fermi, Largo B. Pontecorvo 3, I-56127 Pisa, Italy [email protected] (2) NEST-INFM and Dipartimento di Fisica E. Fermi, Largo B. Pontecorvo 3, I-56127 Pisa, Italy (3) NEST-INFM and Dipartimento di Fisica ...

Application of split-gate structures as tunable spin filters

We describe an electron filter that exploits the known magnetotransport properties of quantum point contacts to provide local and tunable control of the spin polarization in a semiconductor. When properly configured, we show that the conductance of this device gives a direct measure of the spin polarization of carriers transmitted through it. By modeling the transport through a potential barrie...

Scanning gate imaging of quantum point contacts and the origin of the 0.7 anomaly

Graphene based superconducting quantum point contacts

We investigate the Josephson effect in the graphene nanoribbons of length L smaller than the superconducting coherence length and an arbitrary width W . We find that in contrast to an ordinary superconducting quantum point contact (SQPC) the critical supercurrent Ic is not quantized for the nanoribbons with smooth and armchair edges. For a low concentration of the carriers Ic decreases monotoni...