Analytic study of persistent current in a twochannel disordered mesoscopic ring
Abstract
We present an extensive analytical study of persistent current in a weakly disordered twochain cylindrical ring threaded by an AharonovBohm flux 0<φ<φ_{0}/2 (with φ_{0} the flux quantum) and described by the Anderson model. The effect of the disorder reveals a strong reduction of the persistent current for flux values near φ_{0}/4. In conjunction with the pure system (zeroth order) current profile averaged over numbers of electrons and earlier results for the effect of disorder in onedimensional rings, our twochannel results provide a simple interpretation of salient features of the numerical results of Bouchiat and Montambaux (BM) for persistent current in an assembly of manychannel disordered rings. Singlechannel (onedimensional) effects are responsible for the dip in the persistent obtained by BM near φ=0 and the corresponding peak near φ_{0}/2, while the effect of disorder in independent channel pairs accounts for abrupt decreases of current superimposed to a continuous linear decay as the flux value φ_{0}/4 is approached from above and from below, respectively. The persistent current in the twochannel ring involves a free particle current averaged over electron numbers of periodicity φ_{0}/2, and a dominant disorder effect which has periodicity φ_{0}.
 Publication:

Physical Review B
 Pub Date:
 August 2011
 DOI:
 10.1103/PhysRevB.84.075147
 arXiv:
 arXiv:1102.0872
 Bibcode:
 2011PhRvB..84g5147H
 Keywords:

 72.15.Rn;
 73.23.Ra;
 Localization effects;
 Persistent currents;
 Condensed Matter  Disordered Systems and Neural Networks;
 Condensed Matter  Mesoscale and Nanoscale Physics
 EPrint:
 Accepted for publication in Phys. Rev. B