On the possibility of direct observation of the difference between cyclic and zero boundary conditions

The two-dimensional point contacts formed in the inversion layer of GaAs-AlGaAs heterojunctions demonstrate steps in their conductance versus gate potential dependence. It is shown that the step structure depends on the topology of the contact which can be changed from one corresponding to zero boundary conditions, to that appropriate for cyclic ones. The step structure would follow the relation G=(2e²/h)n in the first and G=(2e²/h)(2n+1) in the second case (n=0,1,2,. . .).