Singlet–triplet transitions in highly correlated nanowire quantum dots

• Published in: Physica. E, Low-dimensional systems & nanostructures Vol. 42; no. 4; pp. 837 - 840
• Main Authors: Chen, Y.T., Chao, C.C., Huang, S.Y., Tang, C.S., Cheng, S.J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.2010; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Correlation; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Exchange; Nanowire quantum dot; Physics; Quantum dots; Singlet–triplet transition; Exchange; Correlation; Nanowire quantum dot; Singlet–triplet transition; Quantum system; Zeeman effect; Quantum dots; Singlet-triplet transition; Magnetic field effects; Configuration interaction; Nanowires; Singlet triplet transition; Exchange interactions
• ISSN: 1386-9477; 1873-1759
• DOI: 10.1016/j.physe.2009.11.084

We consider a quantum dot embedded in a three-dimensional nanowire with tunable aspect ratio a. A configuration interaction theory is developed to calculate the energy spectra of the finite 1D quantum dot systems charged with two electrons in the presence of magnetic fields B along the wire axis. Fruitful singlet–triplet transition behaviors are revealed and explained in terms of the competing exchange interaction, correlation interaction, and spin-Zeeman energy. In the high aspect ratio regime, the singlet–triplet transitions are shown designable by tuning the parameters a and B. The transition also manifest the highly correlated nature of long nanowire quantum dots.