NUMERICAL CONFIRMATION OF UNIVERSALITY OF TRANSMISSION MICROSYMMETRY RELATIONS IN A 4-PROBE QUANTUM-DOT

We study the crossover behavior of the Hail resistance between the int eger quantum Hall regime and a regime dominated by the Aharonov-Bohm o scillations, in a system of four-probe quantum dot with an artificial impurity confined inside. In a previous study [M. Lei, N.J. Zhu, and H ong Guo, Phys. Rev. B 52, 16 784 (1995)], a peculiar set of symmetry r elations between various scattering probabilities were found in this c rossover regime. in this paper we examine the universality of this set of symmetry relations using different shapes of the quantum dot and p ositions of the artificial impurity. The symmetry holds for these chan ges, and we conclude that in this transport regime the general behavio r of the Hall resistance is determined by the competition of the quant um Hall and Aharonov-Bohm effects, rather than by the derailed shapes of the structure.