Effects of Fermi energy, dot size, and leads width on weak localization inchaotic quantum dots - art. no. 115310

Magnetotransport in chaotic quantum dots at low magnetic fields is investig ated by means of a tight-binding Hamiltonian on LXL clusters of the square lattice. Chaoticity is induced by introducing L bulk vacancies. The depende nce of weak localization on the Fermi energy, dot size, and leads width is investigated in detail and the results compared with those of previous anal yses, in particular with random matrix theory predictions. Our results indi cate that the dependence of the critical flux Phi (c) on the square root of the number of open modes, as predicted by random matrix theory, is obscure d by the strong energy dependence of the proportionality constant. Instead, the size dependence of the critical flux predicted by Efetov and random ma trix theory, namely, Phi (c)proportional to root1/L, is clearly illustrated by the present results. Our numerical results do also show that the differ ence between conductances at large and zero field tweak localization term) significantly decreases as the leads width W approaches L, reaching a value well below the random matrix theory prediction. A size dependence analysis indicates that the weak localization term remains finite when L increases.