Eur. Phys. J. B 53, 537-549 (2006)
https://doi.org/10.1140/epjb/e2006-00408-2

Theoretical imaging of current profiles in two-dimensional devices

¹ NEST-INFM, Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy and Dipartimento di Fisica `E. Fermi', Università di Pisa, Largo B. Pontecorvo 3, 56127 Pisa, Italy
<sup>2</sup> NEST-INFM and Dipartimento di Fisica `E. Fermi', Università di Pisa, Largo B. Pontecorvo 3, 56127 Pisa, Italy
³ NEST-INFM and Dipartimento di Fisica `A. Volta', Università di Pavia, via A. Bassi 6, 27100 Pavia, Italy

Corresponding author: ^a cresti@df.unipi.it

Received: 7 April 2006
Revised: 29 September 2006
Published online: 17 November 2006

Abstract

This paper addresses in a concise and rigorous way the basic tools for the study of local longitudinal and transverse microscopic currents in two-dimensional devices. The emphasis is on the optimized use of the Keldysh nonequilibrium Green's function theory together with the tight-binding representation of the electronic system. We elaborate general analytic expressions of current profiles, useful for modeling and simulating the local site-to-site flow of carriers; furthermore, in broken time-reversal symmetry, the formalism discerns unambiguously persistent and transport contributions to the bond currents. Our approach achieves a workable theoretical imaging, resolved in space and energy, of the microscopic currents through mesoscopic devices.