Quantum-chaos control in clean and dirty quantum wells coupled by a tunneling transfer

We investigate the electronic properties in tunneling-coupled double quantum wells, one of which has a large degree of disorder and the other of which is relatively clean, based on the spectral statistics of a quantum particle. When a small transfer between the double wells prevents our electronic system from being at the extreme quantum limit in two dimensions, a drastic transformation from a quantum chaotic system to a regular system is driven by the applied electric field threading through the double wells. This effect enables us to control the quantum diffusion in the coupled quantum wells and has a potential application to a functional device which may provide the solution to the traveling-salesman problem, in which the distribution of cities is given by the distribution of electrons generated via electron-hole pair creation in a semiconductor. (C) 2003 Elsevier B.V. All rights reserved.