Magnetoconductance through a chain of rings with or without periodically modulated spin-orbit interaction strength and magnetic field -: art. no. 075330

Ballistic electron transport through a chain of quantum circular rings is studied in the presence of spin-orbit interaction (SOI) and of a perpendicular magnetic field B. From the analytic expressions for the transmission and reflection coefficients for a single ring we obtain the conductance through a chain of rings as a function of the SOI strength alpha, the field B, and of the wave vector k of the incident electron. Due to destructive spin interferences caused by the SOI the chain can be totally opaque for certain ranges of k the width of which depends on the values of alpha and B. Outside these ranges the conductance oscillates with maximum values between e(2)/h and 2e(2)/h. The effect of a periodic modulation of alpha and/or B on the magnetoconductance is also investigated. A periodic, square-wave magnetoconductance pattern results within wide stripes in the parameter space spanned by k, alpha, and B. Finite temperatures smoothen the square-wave profile of the conductance but do not alter its periodic character.