Quantum-transport simulations with the Wigner-function formalism: Failure of conventional boundary-condition schemesD. Taj1, 2, L. Genovese1, 3 and F. Rossi1
1 Dipartimento di Fisica, Politecnico di Torino - 10129 Torino, Italy
2 Dipartimento di Matematica, Università di Torino - 10123 Torino, Italy
3 Dipartimento di Fisica e Sez. INFN, Università di Roma "Tor Vergata" 00133 Roma, Italy
received 8 February 2006; accepted in final form 13 April 2006
published online 12 May 2006
We shall revisit the conventional treatment of open quantum devices based on the Wigner-Function formalism. Our analysis will show that the artificial spatial separation between device active region and external reservoirs -properly defined within a semiclassical simulation scheme- is intrinsically incompatible with the non-local character of quantum mechanics. More specifically, by means of an exactly-solvable semiconductor model, we shall show that the application of the conventional boundary-condition scheme to the Wigner transport equation may produce highly non-physical results, like thermal injection of coherent state superpositions and boundary-driven negative probability distributions.
72.10.Bg - General formulation of transport theory.
85.30.-z - Semiconductor devices.
73.40.-c - Electronic transport in interface structure.
© EDP Sciences 2006