Time-dependent current through a quantum dot in the presence of a voltage probe
Current density evolution as measured behind a quantum dotAbstract
This thesis examines the effects of a Büttiker voltage probe on the time-dependent current through an idealized resonant quantum dot. The system is described by a tight binding Schrödinger equation which is then integrated numerically to obtain the time-dependent current. Correct probe behavior is provided by a time-dependent voltage profile that is obtained numerically via an iterative scheme. The stationary current values are found to be in agreement with predictions derived from the Landauer-Büttiker formalism. The time-dependent current characteristics are significantly affected by the probe-introduced decoherence, as is evident by a shortened time it takes for the current to reach its stationary value. This effect is approximated by a model whose parameter describes the time it takes for the current to reach its stationary value. Examining the data, the parameter values are found to be roughly proportional to the total resonance width of the system.
