The energy level spacing distribution of a tight-binding Hamiltonian is monitored across the mobility edge for a fixed disorder strength. Any mixing of extended and localized levels is avoided in the configurational averages, thus approaching the critical point very closely and with high energy resolution. By finite-size scaling the method is shown to provide a very accurate estimate of the mobility edge and of the critical exponent for a cubic lattice with Lorentzian distributed diagonal disorder. Since no averaging in wide energy windows is required, the method appears as a powerful tool for locating the mobility edges in more complex models of real physical systems.
Mobility edge and level statistics of random tight-binding Hamiltonians
SIRINGO, Fabio;PICCITTO, Giovanni
1998-01-01
Abstract
The energy level spacing distribution of a tight-binding Hamiltonian is monitored across the mobility edge for a fixed disorder strength. Any mixing of extended and localized levels is avoided in the configurational averages, thus approaching the critical point very closely and with high energy resolution. By finite-size scaling the method is shown to provide a very accurate estimate of the mobility edge and of the critical exponent for a cubic lattice with Lorentzian distributed diagonal disorder. Since no averaging in wide energy windows is required, the method appears as a powerful tool for locating the mobility edges in more complex models of real physical systems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
