Transient current in a quantum dot subject to a change in coupling to its leads

• Published in: Journal of physics. Condensed matter Vol. 18; no. 39; pp. 8995 - 9006
• Main Authors: Izmaylov, A F, Goker, A, Friedman, B A, Nordlander, P
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 04.10.2006; Institute of Physics
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; 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; Physics; Quantum dots; Time dependence; Transient response; Kondo effect; Degenerate state; Quantum dots; Tunnel effect; Anderson model; Transport processes
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/18/39/028

The time-dependent non-crossing approximation is used to calculate the transient currents through a quantum dot in the Kondo regime subject to a sudden change in its coupling to the leads. The currents are found to display transient non-universal behaviour immediately after the perturbation and then to follow a slow universal increase toward equilibrium. The timescales for the approach to equilibrium are shown to be the same as those recently identified in a study of transient currents in a quantum dot subject to a sudden change in the energy of the dot level (Plihal et al 2005 Phys. Rev. B 71 165321). We present improved numerical algorithms which enable relatively fast calculation of the transient response of quantum dots to sudden perturbations.