Coulomb correlations and coherent charge tunneling in mesoscopic coupled rings
Department of Applied Physics, Chalmers University of Technology
Göteborg University, S-412 96 Göteborg, Sweden
2 Max-Planck-Institut für Physik komplexer Systeme, Bayreuther Str. 40, D-01187 Dresden, Germany
Accepted: 1 September 1997
We study the effect of a strong electron-electron (e-e) interaction in a system of two concentric one-dimensional rings with incommensurate areas A1 and A2, coupled by a tunnel amplitude. For noninteracting particles the magnetic moment (persistent current) m of the many-body ground state and first excited states is an irregular function of the external magnetic field. In contrast, we show that when strong e-e interactions are present the magnetic-field dependence of m becomes periodic. In such a strongly correlated system disorder can only be caused by inter-ring charge fluctuations, controllable by a gate voltage. The oscillation period of m is if fluctuations are suppressed. Coherent inter-ring tunneling doubles the period when charge fluctuations are allowed.
PACS: 71.27.+a – Strongly correlated electron systems; heavy fermions / 73.20.Dx – Electron states in low-dimensional structures (superlattices, quantum well structures and multilayers) / 72.15.Nj – Collective modes (e.g., in one-dimensional conductors)
© EDP Sciences, 1997