How ubiquitous are dragon segments in quantum transmission?
arXiv:1502.07814
Abstract
Quantum dragon segments are nanodevices that have energy-independent total transmission of electrons. At the level of the single-band tight-binding model a nanodevice is viewed as a weighted undirected graph, with a vertex weight given by the on-site energy and the edge weight given by the tight-binding hopping parameter. A quantum dragon is a weighted undirected graph which when connected to idealized semi-infinite input and output leads, has the electron transmission probability for all electron energies . The probability is obtained from the solution of the time-independent Schrödinger equation. A graph must have finely tuned tight-binding parameters in order to have . This paper addresses classes of weighted graphs which can be tuned, by adjusting a small fraction of the total weights, to be a quantum dragon. We prove that with proper tuning any nanodevice can be a quantum dragon. Three prescriptions are presented to tune a weighted graph into a quantum dragon nanodevice. The implications of the prescriptions for physical nanodevices is discussed.
14 pages, 4 figures