Persistent current in a disordered mesoscopic ring with many channels: Scattering-matrix based calculation

• Published in: Physica. E, Low-dimensional systems & nanostructures Vol. 40; no. 5; pp. 1582 - 1585
• Main Authors: Feilhauer, J., Moško, M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2008; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Disorder; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in mesoscopic systems; Exact sciences and technology; Mesoscopic ring; One-dimensional transport; Persistent current; Physics; Persistent current; 73.61.Ey; Mesoscopic ring; One-dimensional transport; Disorder; 73.23. - b; Persistent currents; Potential barrier; 73.23.-b; 73.61.Ey; One-dimensional transport; Mesoscopic ring; Persistent current; Disorder; Impurities; Mean free path; Roughness; Matrix method; Transport processes; Mesoscopic systems; Scattering matrix
• ISSN: 1386-9477; 1873-1759
• DOI: 10.1016/j.physe.2007.09.116

We calculate numerically the persistent electron current in a disordered quasi-one-dimensional conducting ring with many channels, made of the two-dimensional conductor of finite width W and length L ⪢ W . The elastic mean free path l is limited by two different types of disorder. (i) The impurity disorder is modelled (in two dimensions) by the δ -function-like-potential barriers with random positions and signs. (ii) Disorder due to the sample-edge roughness is modelled as rectangular steps added or subtracted at random at both sample edges. Transport across disorder is described by the scattering-matrix method. Especially in the sample with disordered sample edges, the calculated typical persistent current exceeds remarkably the theoretical result I typ = 1.56 ( ev F / L ) ( l / L ) , known to strongly underestimate experimental data.