Dissipative Quantum Transport in Electron Waveguides
Recent advancements in film growth and patterning have made possible the fabrication of “electron waveguides,” in which transport is analogous to ordinary microwave waveguides. In the past, such devices have been analyzed by assuming that transport is dissipationless, so that the overall transmission between contacts can be computed using the Schrodinger equation. Any device operated at realistic bias levels and temperatures, however, will be influenced by dissipative scattering. Recently, a steady-state quantum kinetic equation has been developed based on a simple model for dissipative processes. In the limit of linear response, this equation can be formulated in terms of a local chemical potential. We use this model to investigate how the chemical potential and current flow pattern are disturbed when a voltage probe is attached to a structure. We show that voltage which is finally measured by the probe is a weighted average of the chemical potential everywhere within a phase-breaking length of the probe junction. Further application of this model to 2-dimensional structures will clarify how to best design a potential probe so that it measures a local quantity.
KeywordsTransmission Coefficient Schrodinger Equation Voltage Probe Straight Wire Quantum Kinetic Equation
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