Long dephasing time and high temperature ballistic transport in an InGaAs quantum dot

Benoit Hackens (1) , Sébastien Faniel (1) , François Delfosse (1) , Cédric Gustin (1) , Hervé Boutry (1) , Isabelle Huynen (1) , X. Wallart (2) , S. Bollaert (2) , A. Cappy (2)

1 CERMIN - Research Center on Micro- and Nanoscopic Electronic Devices and Materials
2 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520

We report on measurements of the magnetoconductance of an open circular InGaAs quantum dot between 1.3 and 204 K. We observe two types of magnetoconductance 5uctuations: universal conductance 5uctuations (UCFs), and “focusing” 5uctuations related to ballistic trajectories between openings. The electron phase coherence time extracted from UCFs amplitude is larger than in GaAs/AlGaAs quantum dots and follows a similar temperature dependence (between T −1 and T −2). Below 150 K, the characteristic length associated with “focusing” 5uctuations shows a slightly di>erent temperature dependence from that of the conductivity.

Mots clés: Quantum dots; Ballistic e>ects; Dephasing

Domaines: Sciences de l'ingénieur [physics]

Benoit Hackens, Sébastien Faniel, François Delfosse, Cédric Gustin, Hervé Boutry, et al.. Long dephasing time and high temperature ballistic transport in an InGaAs quantum dot. Physica E: Low-dimensional Systems and Nanostructures, 2003, 17, pp.143-146. ⟨10.1016/S1386-9477(02)00713-0⟩. ⟨hal-00145986⟩