Coulomb blockade and conductance oscillations in a quantum dot

✍ Scribed by Magnus Persson; Joakim Pettersson; Anders Kristensen; Poul Erik Lindelof

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 156 KB
• Volume: 194-196
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(94)90966-0

✦ Synopsis

We have studied conductance oscillations of a quantum dot by varying the gate potential of one of the gate pairs, that forms the quantum dot, while the other pair was kept at a constant potential. The potential was varied from pinch-off to a level where two or more transverse modes were transmitted through the quantum point contact (QPC). We observed well-pronounced Coulomb-blockade (CB) oscillations when the conductivity of both point contacts was less than 2e2/h. When one QPC was more transparent, conductance oscillations with longer period were observed. The longer period decreased with magnetic field, whereas the short period appeared to be constant. Both oscillations were observed simultaneously at high magnetic fields, even when the conductivity of one QPC was higher than 2e2/h. The conductance oscillations can be explained by charging effects and a variation of tunnel-probability to different Landau levels in the dot.