Classical trajectories at the band center of bipartite lattices with or without vacancies

G. CHIAPPE, E. LOUIS, M. J. SÁNCHEZ AND J. A. VERGÉS

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

Año: 2004 p. 201405 - 201408

0163-1829

Here we report on anomalies in quantum transport at the band center of a bipartite lattice with vacancies, namely: no weak localization effect shows up, and when leads have a single channel the transmission is either one or zero. We propose that both are a consequence of the chiral symmetry and the large number of states at the band center. The probability amplitude associated with the eigenstate that gives unit transmission resembles a classical trajectory both with or without vacancies. The large number of states allows one to build up trajectories that elude the blocking vacancies explaining the absence of weak localization.